diff --git a/py/stencila/schema/interpreter.py b/py/stencila/schema/interpreter.py
index 136382f3..fa04205a 100644
--- a/py/stencila/schema/interpreter.py
+++ b/py/stencila/schema/interpreter.py
@@ -628,7 +628,7 @@ def handle_item(self, item: typing.Any, compilation_result: DocumentCompilationR
             self.traverse_list(item, compilation_result)
         elif isinstance(item, Entity):
             if isinstance(item, (CodeChunk, CodeExpression)):
-                if item.language == self.TARGET_LANGUAGE:  # Only add Python code
+                if item.programmingLanguage == self.TARGET_LANGUAGE:  # Only add Python code
                     self.handle_code(item, compilation_result)
 
             elif isinstance(item, Parameter) and self.function_depth == 0:
diff --git a/py/stencila/schema/types.py b/py/stencila/schema/types.py
index 2f2cef1b..833f9126 100644
--- a/py/stencila/schema/types.py
+++ b/py/stencila/schema/types.py
@@ -9,9 +9,9 @@
 
 EItemListOrder = Enum("ItemListOrder", ["ascending", "descending", "unordered"])
 
-ETableCellKind = Enum("TableCellKind", ["data", "header"])
+ECellType = Enum("CellType", ["data", "header"])
 
-ETableRowKind = Enum("TableRowKind", ["header", "footer"])
+ERowType = Enum("RowType", ["header", "footer"])
 
 
 class Entity:
@@ -89,6 +89,7 @@ class Cite(Entity):
 
     target: str
     citationMode: Optional["ECitationMode"] = None
+    content: Optional[Array["InlineContent"]] = None
     pageEnd: Optional[Union[str, int]] = None
     pageStart: Optional[Union[str, int]] = None
     pagination: Optional[str] = None
@@ -99,6 +100,7 @@ def __init__(
         self,
         target: str,
         citationMode: Optional["ECitationMode"] = None,
+        content: Optional[Array["InlineContent"]] = None,
         id: Optional[str] = None,
         meta: Optional[Dict[str, Any]] = None,
         pageEnd: Optional[Union[str, int]] = None,
@@ -115,6 +117,8 @@ def __init__(
             self.target = target
         if citationMode is not None:
             self.citationMode = citationMode
+        if content is not None:
+            self.content = content
         if pageEnd is not None:
             self.pageEnd = pageEnd
         if pageStart is not None:
@@ -150,14 +154,14 @@ class Code(Entity):
     """Inline code."""
 
     text: str
-    language: Optional[str] = None
+    programmingLanguage: Optional[str] = None
 
     def __init__(
         self,
         text: str,
         id: Optional[str] = None,
-        language: Optional[str] = None,
-        meta: Optional[Dict[str, Any]] = None
+        meta: Optional[Dict[str, Any]] = None,
+        programmingLanguage: Optional[str] = None
     ) -> None:
         super().__init__(
             id=id,
@@ -165,8 +169,8 @@ def __init__(
         )
         if text is not None:
             self.text = text
-        if language is not None:
-            self.language = language
+        if programmingLanguage is not None:
+            self.programmingLanguage = programmingLanguage
 
 
 class CodeBlock(Code):
@@ -176,14 +180,14 @@ def __init__(
         self,
         text: str,
         id: Optional[str] = None,
-        language: Optional[str] = None,
-        meta: Optional[Dict[str, Any]] = None
+        meta: Optional[Dict[str, Any]] = None,
+        programmingLanguage: Optional[str] = None
     ) -> None:
         super().__init__(
             text=text,
             id=id,
-            language=language,
-            meta=meta
+            meta=meta,
+            programmingLanguage=programmingLanguage
         )
 
 
@@ -211,17 +215,17 @@ def __init__(
         errors: Optional[Array["CodeError"]] = None,
         id: Optional[str] = None,
         imports: Optional[Array[Union[str, "SoftwareSourceCode", "SoftwareApplication"]]] = None,
-        language: Optional[str] = None,
         meta: Optional[Dict[str, Any]] = None,
         outputs: Optional[Array["Node"]] = None,
+        programmingLanguage: Optional[str] = None,
         reads: Optional[Array[str]] = None,
         uses: Optional[Array[Union[str, "Variable"]]] = None
     ) -> None:
         super().__init__(
             text=text,
             id=id,
-            language=language,
-            meta=meta
+            meta=meta,
+            programmingLanguage=programmingLanguage
         )
         if alters is not None:
             self.alters = alters
@@ -250,14 +254,14 @@ def __init__(
         self,
         text: str,
         id: Optional[str] = None,
-        language: Optional[str] = None,
-        meta: Optional[Dict[str, Any]] = None
+        meta: Optional[Dict[str, Any]] = None,
+        programmingLanguage: Optional[str] = None
     ) -> None:
         super().__init__(
             text=text,
             id=id,
-            language=language,
-            meta=meta
+            meta=meta,
+            programmingLanguage=programmingLanguage
         )
 
 
@@ -273,15 +277,15 @@ def __init__(
         text: str,
         errors: Optional[Array["CodeError"]] = None,
         id: Optional[str] = None,
-        language: Optional[str] = None,
         meta: Optional[Dict[str, Any]] = None,
-        output: Optional["Node"] = None
+        output: Optional["Node"] = None,
+        programmingLanguage: Optional[str] = None
     ) -> None:
         super().__init__(
             text=text,
             id=id,
-            language=language,
-            meta=meta
+            meta=meta,
+            programmingLanguage=programmingLanguage
         )
         if errors is not None:
             self.errors = errors
@@ -335,6 +339,25 @@ def __init__(
             self.value = value
 
 
+class Date(Entity):
+    """A date encoded as a ISO 8601 string."""
+
+    value: str
+
+    def __init__(
+        self,
+        value: str,
+        id: Optional[str] = None,
+        meta: Optional[Dict[str, Any]] = None
+    ) -> None:
+        super().__init__(
+            id=id,
+            meta=meta
+        )
+        if value is not None:
+            self.value = value
+
+
 class Mark(Entity):
     """
     A base class for nodes that mark some other inline content in some way
@@ -460,11 +483,11 @@ def __init__(
 
 
 class ContactPoint(Thing):
-    """A contact point—for example, a R&D department."""
+    """A contact point, for example, a R&D department."""
 
     availableLanguages: Optional[Array[str]] = None
     emails: Optional[Array[str]] = None
-    telephone: Optional[str] = None
+    telephoneNumbers: Optional[Array[str]] = None
 
     def __init__(
         self,
@@ -475,7 +498,7 @@ def __init__(
         id: Optional[str] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
-        telephone: Optional[str] = None,
+        telephoneNumbers: Optional[Array[str]] = None,
         url: Optional[str] = None
     ) -> None:
         super().__init__(
@@ -490,8 +513,8 @@ def __init__(
             self.availableLanguages = availableLanguages
         if emails is not None:
             self.emails = emails
-        if telephone is not None:
-            self.telephone = telephone
+        if telephoneNumbers is not None:
+            self.telephoneNumbers = telephoneNumbers
 
 
 class CreativeWork(Thing):
@@ -502,12 +525,13 @@ class CreativeWork(Thing):
 
     authors: Optional[Array[Union["Person", "Organization"]]] = None
     content: Optional[Array["Node"]] = None
-    dateCreated: Optional[str] = None
-    dateModified: Optional[str] = None
-    datePublished: Optional[str] = None
+    dateCreated: Optional[Union["Date", str]] = None
+    dateModified: Optional[Union["Date", str]] = None
+    datePublished: Optional[Union["Date", str]] = None
     editors: Optional[Array["Person"]] = None
     funders: Optional[Array[Union["Person", "Organization"]]] = None
     isPartOf: Optional["CreativeWorkTypes"] = None
+    keywords: Optional[Array[str]] = None
     licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None
     parts: Optional[Array["CreativeWorkTypes"]] = None
     publisher: Optional[Union["Person", "Organization"]] = None
@@ -521,14 +545,15 @@ def __init__(
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -564,6 +589,8 @@ def __init__(
             self.funders = funders
         if isPartOf is not None:
             self.isPartOf = isPartOf
+        if keywords is not None:
+            self.keywords = keywords
         if licenses is not None:
             self.licenses = licenses
         if parts is not None:
@@ -593,15 +620,16 @@ def __init__(
         title: str,
         alternateNames: Optional[Array[str]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         environment: Optional["Environment"] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -625,6 +653,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -654,14 +683,15 @@ def __init__(
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -685,6 +715,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -710,14 +741,15 @@ def __init__(
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -741,6 +773,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -776,9 +809,9 @@ def __init__(
         bitrate: Optional[float] = None,
         content: Optional[Array["Node"]] = None,
         contentSize: Optional[float] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         embedUrl: Optional[str] = None,
@@ -786,6 +819,7 @@ def __init__(
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -809,6 +843,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -847,9 +882,9 @@ def __init__(
         caption: Optional[str] = None,
         content: Optional[Array["Node"]] = None,
         contentSize: Optional[float] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         embedUrl: Optional[str] = None,
@@ -857,6 +892,7 @@ def __init__(
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -886,6 +922,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -963,7 +1000,6 @@ class Environment(Thing):
     adds: Optional[Array["SoftwareSourceCode"]] = None
     extends: Optional[Array["Environment"]] = None
     removes: Optional[Array["SoftwareSourceCode"]] = None
-    source: Optional[str] = None
 
     def __init__(
         self,
@@ -975,7 +1011,6 @@ def __init__(
         id: Optional[str] = None,
         meta: Optional[Dict[str, Any]] = None,
         removes: Optional[Array["SoftwareSourceCode"]] = None,
-        source: Optional[str] = None,
         url: Optional[str] = None
     ) -> None:
         super().__init__(
@@ -994,8 +1029,6 @@ def __init__(
             self.extends = extends
         if removes is not None:
             self.removes = removes
-        if source is not None:
-            self.source = source
 
 
 class Figure(CreativeWork):
@@ -1013,14 +1046,15 @@ def __init__(
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         caption: Optional[Array["Node"]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         label: Optional[str] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
@@ -1045,6 +1079,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -1130,9 +1165,9 @@ def __init__(
         caption: Optional[str] = None,
         content: Optional[Array["Node"]] = None,
         contentSize: Optional[float] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         embedUrl: Optional[str] = None,
@@ -1140,6 +1175,7 @@ def __init__(
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -1169,6 +1205,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -1538,8 +1575,8 @@ def __init__(
 class Periodical(CreativeWork):
     """A periodical publication."""
 
-    dateEnd: Optional[str] = None
-    dateStart: Optional[str] = None
+    dateEnd: Optional[Union["Date", str]] = None
+    dateStart: Optional[Union["Date", str]] = None
     issn: Optional[Array[str]] = None
 
     def __init__(
@@ -1547,17 +1584,18 @@ def __init__(
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateEnd: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
-        dateStart: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateEnd: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
+        dateStart: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
         issn: Optional[Array[str]] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -1581,6 +1619,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -1673,14 +1712,14 @@ class Product(Thing):
     an episode of a TV show streamed online.
     """
 
-    brand: Optional["Brand"] = None
+    brands: Optional[Array["Brand"]] = None
     logo: Optional[Union[str, "ImageObject"]] = None
     productID: Optional[str] = None
 
     def __init__(
         self,
         alternateNames: Optional[Array[str]] = None,
-        brand: Optional["Brand"] = None,
+        brands: Optional[Array["Brand"]] = None,
         description: Optional[str] = None,
         id: Optional[str] = None,
         logo: Optional[Union[str, "ImageObject"]] = None,
@@ -1697,8 +1736,8 @@ def __init__(
             name=name,
             url=url
         )
-        if brand is not None:
-            self.brand = brand
+        if brands is not None:
+            self.brands = brands
         if logo is not None:
             self.logo = logo
         if productID is not None:
@@ -1708,7 +1747,7 @@ def __init__(
 class PublicationIssue(CreativeWork):
     """
     A part of a successively published publication such as a periodical or
-    publication  volume, often numbered.
+    publication volume, often numbered.
     """
 
     issueNumber: Optional[Union[str, int]] = None
@@ -1721,15 +1760,16 @@ def __init__(
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
         issueNumber: Optional[Union[str, int]] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -1756,6 +1796,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -1793,14 +1834,15 @@ def __init__(
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -1828,6 +1870,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -1852,12 +1895,12 @@ def __init__(
 class Quote(Mark):
     """Inline, quoted content."""
 
-    citation: Optional[str] = None
+    cite: Optional[Union["Cite", str]] = None
 
     def __init__(
         self,
         content: Array["InlineContent"],
-        citation: Optional[str] = None,
+        cite: Optional[Union["Cite", str]] = None,
         id: Optional[str] = None,
         meta: Optional[Dict[str, Any]] = None
     ) -> None:
@@ -1866,20 +1909,20 @@ def __init__(
             id=id,
             meta=meta
         )
-        if citation is not None:
-            self.citation = citation
+        if cite is not None:
+            self.cite = cite
 
 
 class QuoteBlock(Entity):
     """A section quoted from somewhere else."""
 
     content: Array["BlockContent"]
-    citation: Optional[str] = None
+    cite: Optional[Union["Cite", str]] = None
 
     def __init__(
         self,
         content: Array["BlockContent"],
-        citation: Optional[str] = None,
+        cite: Optional[Union["Cite", str]] = None,
         id: Optional[str] = None,
         meta: Optional[Dict[str, Any]] = None
     ) -> None:
@@ -1889,8 +1932,8 @@ def __init__(
         )
         if content is not None:
             self.content = content
-        if citation is not None:
-            self.citation = citation
+        if cite is not None:
+            self.cite = cite
 
 
 class ResourceParameters(Thing):
@@ -1938,14 +1981,15 @@ def __init__(
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -1971,6 +2015,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -2051,14 +2096,15 @@ def __init__(
         codeRepository: Optional[str] = None,
         codeSampleType: Optional[str] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         maintainers: Optional[Array[Union["Organization", "Person"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
@@ -2087,6 +2133,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -2203,14 +2250,15 @@ def __init__(
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         content: Optional[Array["Node"]] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -2234,6 +2282,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
@@ -2253,17 +2302,17 @@ class TableCell(Entity):
     """A cell within a `Table`."""
 
     content: Array["InlineContent"]
+    cellType: Optional["ECellType"] = None
     colspan: Optional[int] = None
-    kind: Optional["ETableCellKind"] = None
     name: Optional[str] = None
     rowspan: Optional[int] = None
 
     def __init__(
         self,
         content: Array["InlineContent"],
+        cellType: Optional["ECellType"] = None,
         colspan: Optional[int] = None,
         id: Optional[str] = None,
-        kind: Optional["ETableCellKind"] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
         rowspan: Optional[int] = None
@@ -2274,10 +2323,10 @@ def __init__(
         )
         if content is not None:
             self.content = content
+        if cellType is not None:
+            self.cellType = cellType
         if colspan is not None:
             self.colspan = colspan
-        if kind is not None:
-            self.kind = kind
         if name is not None:
             self.name = name
         if rowspan is not None:
@@ -2288,14 +2337,14 @@ class TableRow(Entity):
     """A row within a Table."""
 
     cells: Array["TableCell"]
-    kind: Optional["ETableRowKind"] = None
+    rowType: Optional["ERowType"] = None
 
     def __init__(
         self,
         cells: Array["TableCell"],
         id: Optional[str] = None,
-        kind: Optional["ETableRowKind"] = None,
-        meta: Optional[Dict[str, Any]] = None
+        meta: Optional[Dict[str, Any]] = None,
+        rowType: Optional["ERowType"] = None
     ) -> None:
         super().__init__(
             id=id,
@@ -2303,8 +2352,8 @@ def __init__(
         )
         if cells is not None:
             self.cells = cells
-        if kind is not None:
-            self.kind = kind
+        if rowType is not None:
+            self.rowType = rowType
 
 
 class ThematicBreak(Entity):
@@ -2360,9 +2409,9 @@ def __init__(
         caption: Optional[str] = None,
         content: Optional[Array["Node"]] = None,
         contentSize: Optional[float] = None,
-        dateCreated: Optional[str] = None,
-        dateModified: Optional[str] = None,
-        datePublished: Optional[str] = None,
+        dateCreated: Optional[Union["Date", str]] = None,
+        dateModified: Optional[Union["Date", str]] = None,
+        datePublished: Optional[Union["Date", str]] = None,
         description: Optional[str] = None,
         editors: Optional[Array["Person"]] = None,
         embedUrl: Optional[str] = None,
@@ -2370,6 +2419,7 @@ def __init__(
         funders: Optional[Array[Union["Person", "Organization"]]] = None,
         id: Optional[str] = None,
         isPartOf: Optional["CreativeWorkTypes"] = None,
+        keywords: Optional[Array[str]] = None,
         licenses: Optional[Array[Union[str, "CreativeWorkTypes"]]] = None,
         meta: Optional[Dict[str, Any]] = None,
         name: Optional[str] = None,
@@ -2400,6 +2450,7 @@ def __init__(
             funders=funders,
             id=id,
             isPartOf=isPartOf,
+            keywords=keywords,
             licenses=licenses,
             meta=meta,
             name=name,
diff --git a/py/tests/test_document_compiler.py b/py/tests/test_document_compiler.py
index d2455071..9fd0831f 100644
--- a/py/tests/test_document_compiler.py
+++ b/py/tests/test_document_compiler.py
@@ -35,22 +35,22 @@ def test_compile_article():
             {
                 'type': 'CodeChunk',
                 'text': 'let a = \'I am JavaScript!\'',
-                'language': 'notpython'
+                'programmingLanguage': 'notpython'
             },
             {
                 'type': 'CodeChunk',
                 'text': chunk_1_text,
-                'language': 'python'
+                'programmingLanguage': 'python'
             },
             {
                 'type': 'CodeChunk',
                 'text': chunk_2_text,
-                'language': 'python'
+                'programmingLanguage': 'python'
             },
             {
                 'type': 'CodeChunk',
                 'text': chunk_3_text,
-                'language': 'python',
+                'programmingLanguage': 'python',
                 'declares': [
                     {
                         'type': 'Function',
@@ -68,17 +68,17 @@ def test_compile_article():
             {
                 'type': 'CodeExpression',
                 'text': 'invalid code',
-                'language': 'notpython'
+                'programmingLanguage': 'notpython'
             },
             {
                 'type': 'CodeExpression',
                 'text': expr_1_text,
-                'language': 'python'
+                'programmingLanguage': 'python'
             },
             {
                 'type': 'CodeExpression',
                 'text': expr_2_text,
-                'language': 'python'
+                'programmingLanguage': 'python'
             }
         ]
     })
@@ -96,7 +96,7 @@ def test_compile_article():
     for c in dcr.code:
         if isinstance(c, CodeChunkExecution):
             c = c[0]
-        assert c.language == 'python'
+        assert c.programmingLanguage == 'python'
 
     code_chunks = list(map(lambda c: c[0], filter(lambda ce: isinstance(ce, CodeChunkExecution), dcr.code)))
     code_exprs = list(filter(lambda ce: isinstance(ce, CodeExpression), dcr.code))
@@ -111,7 +111,7 @@ def test_compile_article():
 
 def test_import_appending():
     """Found imports in a piece of code should be added to the list of imports the code chunk already specifies."""
-    c = CodeChunk('import moda\nimport modb\nimport modc', imports=['modc', 'modd'], language='python')
+    c = CodeChunk('import moda\nimport modb\nimport modc', imports=['modc', 'modd'], programmingLanguage='python')
 
     dc = DocumentCompiler()
     dc.compile(c)
@@ -125,7 +125,7 @@ def test_import_appending():
 
 def test_import_with_semaphore():
     """If a `CodeChunk`'s imports has an empty string element then no imports should be added to its list."""
-    c = CodeChunk('import moda\nimport modb', imports=['modc', 'modd', ''])
+    c = CodeChunk('import moda\nimport modb', imports=['modc', 'modd', ''], programmingLanguage='python')
 
     dc = DocumentCompiler()
     dc.compile(c)
diff --git a/r/R/types.R b/r/R/types.R
index a5bd5a1f..a18f4092 100644
--- a/r/R/types.R
+++ b/r/R/types.R
@@ -87,6 +87,7 @@ BooleanSchema <- function(
 #' @name Cite
 #' @param target The target of the citation (URL or reference ID). \bold{Required}.
 #' @param citationMode How the cite is rendered in the surrounding text.
+#' @param content Optional structured content/text of this citation.
 #' @param id The identifier for this item.
 #' @param meta Metadata associated with this item.
 #' @param pageEnd The page on which the work ends; for example "138" or "xvi".
@@ -99,6 +100,7 @@ BooleanSchema <- function(
 Cite <- function(
   target,
   citationMode,
+  content,
   id,
   meta,
   pageEnd,
@@ -114,6 +116,7 @@ Cite <- function(
   self$type <- as_scalar("Cite")
   self[["target"]] <- check_property("Cite", "target", TRUE, missing(target), "character", target)
   self[["citationMode"]] <- check_property("Cite", "citationMode", FALSE, missing(citationMode), Enum("normal", "suppressAuthor"), citationMode)
+  self[["content"]] <- check_property("Cite", "content", FALSE, missing(content), Array("InlineContent"), content)
   self[["pageEnd"]] <- check_property("Cite", "pageEnd", FALSE, missing(pageEnd), Union("character", "numeric"), pageEnd)
   self[["pageStart"]] <- check_property("Cite", "pageStart", FALSE, missing(pageStart), Union("character", "numeric"), pageStart)
   self[["pagination"]] <- check_property("Cite", "pagination", FALSE, missing(pagination), "character", pagination)
@@ -153,15 +156,15 @@ CiteGroup <- function(
 #' @name Code
 #' @param text The text of the code. \bold{Required}.
 #' @param id The identifier for this item.
-#' @param language The programming language of the code.
 #' @param meta Metadata associated with this item.
+#' @param programmingLanguage The programming language of the code.
 #' @seealso \code{\link{Entity}}
 #' @export
 Code <- function(
   text,
   id,
-  language,
-  meta
+  meta,
+  programmingLanguage
 ){
   self <- Entity(
     id = id,
@@ -169,7 +172,7 @@ Code <- function(
   )
   self$type <- as_scalar("Code")
   self[["text"]] <- check_property("Code", "text", TRUE, missing(text), "character", text)
-  self[["language"]] <- check_property("Code", "language", FALSE, missing(language), "character", language)
+  self[["programmingLanguage"]] <- check_property("Code", "programmingLanguage", FALSE, missing(programmingLanguage), "character", programmingLanguage)
   class(self) <- c("list", "Entity")
   self
 }
@@ -180,21 +183,21 @@ Code <- function(
 #' @name CodeBlock
 #' @param text The text of the code. \bold{Required}.
 #' @param id The identifier for this item.
-#' @param language The programming language of the code.
 #' @param meta Metadata associated with this item.
+#' @param programmingLanguage The programming language of the code.
 #' @seealso \code{\link{Code}}
 #' @export
 CodeBlock <- function(
   text,
   id,
-  language,
-  meta
+  meta,
+  programmingLanguage
 ){
   self <- Code(
     text = text,
     id = id,
-    language = language,
-    meta = meta
+    meta = meta,
+    programmingLanguage = programmingLanguage
   )
   self$type <- as_scalar("CodeBlock")
 
@@ -214,9 +217,9 @@ CodeBlock <- function(
 #' @param errors Errors when compiling or executing the chunk.
 #' @param id The identifier for this item.
 #' @param imports Software packages that the code chunk imports
-#' @param language The programming language of the code.
 #' @param meta Metadata associated with this item.
 #' @param outputs Outputs from executing the chunk.
+#' @param programmingLanguage The programming language of the code.
 #' @param reads Filesystem paths that this code chunk reads from.
 #' @param uses Names of variables that the code chunk uses (but does not alter).
 #' @seealso \code{\link{CodeBlock}}
@@ -230,17 +233,17 @@ CodeChunk <- function(
   errors,
   id,
   imports,
-  language,
   meta,
   outputs,
+  programmingLanguage,
   reads,
   uses
 ){
   self <- CodeBlock(
     text = text,
     id = id,
-    language = language,
-    meta = meta
+    meta = meta,
+    programmingLanguage = programmingLanguage
   )
   self$type <- as_scalar("CodeChunk")
   self[["alters"]] <- check_property("CodeChunk", "alters", FALSE, missing(alters), Array("character"), alters)
@@ -262,21 +265,21 @@ CodeChunk <- function(
 #' @name CodeFragment
 #' @param text The text of the code. \bold{Required}.
 #' @param id The identifier for this item.
-#' @param language The programming language of the code.
 #' @param meta Metadata associated with this item.
+#' @param programmingLanguage The programming language of the code.
 #' @seealso \code{\link{Code}}
 #' @export
 CodeFragment <- function(
   text,
   id,
-  language,
-  meta
+  meta,
+  programmingLanguage
 ){
   self <- Code(
     text = text,
     id = id,
-    language = language,
-    meta = meta
+    meta = meta,
+    programmingLanguage = programmingLanguage
   )
   self$type <- as_scalar("CodeFragment")
 
@@ -291,24 +294,24 @@ CodeFragment <- function(
 #' @param text The text of the code. \bold{Required}.
 #' @param errors Errors when compiling or executing the chunk.
 #' @param id The identifier for this item.
-#' @param language The programming language of the code.
 #' @param meta Metadata associated with this item.
 #' @param output The value of the expression when it was last evaluated.
+#' @param programmingLanguage The programming language of the code.
 #' @seealso \code{\link{CodeFragment}}
 #' @export
 CodeExpression <- function(
   text,
   errors,
   id,
-  language,
   meta,
-  output
+  output,
+  programmingLanguage
 ){
   self <- CodeFragment(
     text = text,
     id = id,
-    language = language,
-    meta = meta
+    meta = meta,
+    programmingLanguage = programmingLanguage
   )
   self$type <- as_scalar("CodeExpression")
   self[["errors"]] <- check_property("CodeExpression", "errors", FALSE, missing(errors), Array("CodeError"), errors)
@@ -372,6 +375,30 @@ ConstantSchema <- function(
 }
 
 
+#' A date encoded as a ISO 8601 string.
+#'
+#' @name Date
+#' @param value The date as an ISO 8601 string. \bold{Required}.
+#' @param id The identifier for this item.
+#' @param meta Metadata associated with this item.
+#' @seealso \code{\link{Entity}}
+#' @export
+Date <- function(
+  value,
+  id,
+  meta
+){
+  self <- Entity(
+    id = id,
+    meta = meta
+  )
+  self$type <- as_scalar("Date")
+  self[["value"]] <- check_property("Date", "value", TRUE, missing(value), "character", value)
+  class(self) <- c("list", "Entity")
+  self
+}
+
+
 #' A base class for nodes that mark some other inline content in some way (e.g. as being emphasised, or quoted).
 #'
 #' @name Mark
@@ -519,7 +546,7 @@ Brand <- function(
 }
 
 
-#' A contact point—for example, a R&D department.
+#' A contact point, for example, a R&D department.
 #'
 #' @name ContactPoint
 #' @param alternateNames Alternate names (aliases) for the item.
@@ -529,7 +556,7 @@ Brand <- function(
 #' @param id The identifier for this item.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
-#' @param telephone The telephone number of the contact point. Accepted formats: +44 123455, (02)12345, 006645667.
+#' @param telephoneNumbers Telephone numbers for the contact point.
 #' @param url The URL of the item.
 #' @seealso \code{\link{Thing}}
 #' @export
@@ -541,7 +568,7 @@ ContactPoint <- function(
   id,
   meta,
   name,
-  telephone,
+  telephoneNumbers,
   url
 ){
   self <- Thing(
@@ -555,7 +582,7 @@ ContactPoint <- function(
   self$type <- as_scalar("ContactPoint")
   self[["availableLanguages"]] <- check_property("ContactPoint", "availableLanguages", FALSE, missing(availableLanguages), Array("character"), availableLanguages)
   self[["emails"]] <- check_property("ContactPoint", "emails", FALSE, missing(emails), Array("character"), emails)
-  self[["telephone"]] <- check_property("ContactPoint", "telephone", FALSE, missing(telephone), "character", telephone)
+  self[["telephoneNumbers"]] <- check_property("ContactPoint", "telephoneNumbers", FALSE, missing(telephoneNumbers), Array("character"), telephoneNumbers)
   class(self) <- c("list", "Entity")
   self
 }
@@ -575,6 +602,7 @@ ContactPoint <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -599,6 +627,7 @@ CreativeWork <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -621,12 +650,13 @@ CreativeWork <- function(
   self$type <- as_scalar("CreativeWork")
   self[["authors"]] <- check_property("CreativeWork", "authors", FALSE, missing(authors), Array(Union("Person", "Organization")), authors)
   self[["content"]] <- check_property("CreativeWork", "content", FALSE, missing(content), Array("Node"), content)
-  self[["dateCreated"]] <- check_property("CreativeWork", "dateCreated", FALSE, missing(dateCreated), "character", dateCreated)
-  self[["dateModified"]] <- check_property("CreativeWork", "dateModified", FALSE, missing(dateModified), "character", dateModified)
-  self[["datePublished"]] <- check_property("CreativeWork", "datePublished", FALSE, missing(datePublished), "character", datePublished)
+  self[["dateCreated"]] <- check_property("CreativeWork", "dateCreated", FALSE, missing(dateCreated), Union("Date", "character"), dateCreated)
+  self[["dateModified"]] <- check_property("CreativeWork", "dateModified", FALSE, missing(dateModified), Union("Date", "character"), dateModified)
+  self[["datePublished"]] <- check_property("CreativeWork", "datePublished", FALSE, missing(datePublished), Union("Date", "character"), datePublished)
   self[["editors"]] <- check_property("CreativeWork", "editors", FALSE, missing(editors), Array("Person"), editors)
   self[["funders"]] <- check_property("CreativeWork", "funders", FALSE, missing(funders), Array(Union("Person", "Organization")), funders)
   self[["isPartOf"]] <- check_property("CreativeWork", "isPartOf", FALSE, missing(isPartOf), "CreativeWorkTypes", isPartOf)
+  self[["keywords"]] <- check_property("CreativeWork", "keywords", FALSE, missing(keywords), Array("character"), keywords)
   self[["licenses"]] <- check_property("CreativeWork", "licenses", FALSE, missing(licenses), Array(Union("character", "CreativeWorkTypes")), licenses)
   self[["parts"]] <- check_property("CreativeWork", "parts", FALSE, missing(parts), Array("CreativeWorkTypes"), parts)
   self[["publisher"]] <- check_property("CreativeWork", "publisher", FALSE, missing(publisher), Union("Person", "Organization"), publisher)
@@ -655,6 +685,7 @@ CreativeWork <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -680,6 +711,7 @@ Article <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -703,6 +735,7 @@ Article <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -737,6 +770,7 @@ Article <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -761,6 +795,7 @@ Collection <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -784,6 +819,7 @@ Collection <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -816,6 +852,7 @@ Collection <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -841,6 +878,7 @@ Datatable <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -864,6 +902,7 @@ Datatable <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -901,6 +940,7 @@ Datatable <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -930,6 +970,7 @@ MediaObject <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -953,6 +994,7 @@ MediaObject <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -995,6 +1037,7 @@ MediaObject <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -1026,6 +1069,7 @@ AudioObject <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -1055,6 +1099,7 @@ AudioObject <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -1149,7 +1194,6 @@ EnumSchema <- function(
 #' @param id The identifier for this item.
 #' @param meta Metadata associated with this item.
 #' @param removes The packages that this environment removes from the base environments listed under `extends` (if any).,
-#' @param source Source of environment definition. e.g. a URL to a Dockerfile, or a path to a filesystem folder.
 #' @param url The URL of the item.
 #' @seealso \code{\link{Thing}}
 #' @export
@@ -1162,7 +1206,6 @@ Environment <- function(
   id,
   meta,
   removes,
-  source,
   url
 ){
   self <- Thing(
@@ -1178,7 +1221,6 @@ Environment <- function(
   self[["adds"]] <- check_property("Environment", "adds", FALSE, missing(adds), Array("SoftwareSourceCode"), adds)
   self[["extends"]] <- check_property("Environment", "extends", FALSE, missing(extends), Array("Environment"), extends)
   self[["removes"]] <- check_property("Environment", "removes", FALSE, missing(removes), Array("SoftwareSourceCode"), removes)
-  self[["source"]] <- check_property("Environment", "source", FALSE, missing(source), "character", source)
   class(self) <- c("list", "Entity")
   self
 }
@@ -1199,6 +1241,7 @@ Environment <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param label A short label for the figure.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
@@ -1225,6 +1268,7 @@ Figure <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   label,
   licenses,
   meta,
@@ -1249,6 +1293,7 @@ Figure <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -1345,6 +1390,7 @@ Heading <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -1376,6 +1422,7 @@ ImageObject <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -1405,6 +1452,7 @@ ImageObject <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -1829,6 +1877,7 @@ Parameter <- function(
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
 #' @param issn The International Standard Serial Number (ISSN) that identifies this serial publication.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -1856,6 +1905,7 @@ Periodical <- function(
   id,
   isPartOf,
   issn,
+  keywords,
   licenses,
   meta,
   name,
@@ -1879,6 +1929,7 @@ Periodical <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -1891,8 +1942,8 @@ Periodical <- function(
     version = version
   )
   self$type <- as_scalar("Periodical")
-  self[["dateEnd"]] <- check_property("Periodical", "dateEnd", FALSE, missing(dateEnd), "character", dateEnd)
-  self[["dateStart"]] <- check_property("Periodical", "dateStart", FALSE, missing(dateStart), "character", dateStart)
+  self[["dateEnd"]] <- check_property("Periodical", "dateEnd", FALSE, missing(dateEnd), Union("Date", "character"), dateEnd)
+  self[["dateStart"]] <- check_property("Periodical", "dateStart", FALSE, missing(dateStart), Union("Date", "character"), dateStart)
   self[["issn"]] <- check_property("Periodical", "issn", FALSE, missing(issn), Array("character"), issn)
   class(self) <- c("list", "Entity")
   self
@@ -1969,7 +2020,7 @@ Person <- function(
 #'
 #' @name Product
 #' @param alternateNames Alternate names (aliases) for the item.
-#' @param brand Brand that the product is labelled with.
+#' @param brands Brands that the product is labelled with.
 #' @param description A description of the item.
 #' @param id The identifier for this item.
 #' @param logo The logo of the product.
@@ -1981,7 +2032,7 @@ Person <- function(
 #' @export
 Product <- function(
   alternateNames,
-  brand,
+  brands,
   description,
   id,
   logo,
@@ -1999,7 +2050,7 @@ Product <- function(
     url = url
   )
   self$type <- as_scalar("Product")
-  self[["brand"]] <- check_property("Product", "brand", FALSE, missing(brand), "Brand", brand)
+  self[["brands"]] <- check_property("Product", "brands", FALSE, missing(brands), Array("Brand"), brands)
   self[["logo"]] <- check_property("Product", "logo", FALSE, missing(logo), Union("character", "ImageObject"), logo)
   self[["productID"]] <- check_property("Product", "productID", FALSE, missing(productID), "character", productID)
   class(self) <- c("list", "Entity")
@@ -2007,7 +2058,7 @@ Product <- function(
 }
 
 
-#' A part of a successively published publication such as a periodical or publication  volume, often numbered.
+#' A part of a successively published publication such as a periodical or publication volume, often numbered.
 #'
 #' @name PublicationIssue
 #' @param alternateNames Alternate names (aliases) for the item.
@@ -2022,12 +2073,13 @@ Product <- function(
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
 #' @param issueNumber Identifies the issue of publication; for example, "iii" or "2".
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
 #' @param pageEnd The page on which the work ends; for example "138" or "xvi".
 #' @param pageStart The page on which the work starts; for example "135" or "xiii".
-#' @param pagination Any description of pages that is not separated into pageStart and pageEnd;  for example, "1-6, 9, 55".
+#' @param pagination Any description of pages that is not separated into pageStart and pageEnd; for example, "1-6, 9, 55".
 #' @param parts Elements of the collection which can be a variety of different elements, such as Articles, Datatables, Tables and more.
 #' @param publisher A publisher of the CreativeWork.
 #' @param references References to other creative works, such as another publication, web page, scholarly article, etc.
@@ -2050,6 +2102,7 @@ PublicationIssue <- function(
   id,
   isPartOf,
   issueNumber,
+  keywords,
   licenses,
   meta,
   name,
@@ -2076,6 +2129,7 @@ PublicationIssue <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -2111,6 +2165,7 @@ PublicationIssue <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -2139,6 +2194,7 @@ PublicationVolume <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -2166,6 +2222,7 @@ PublicationVolume <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -2191,14 +2248,14 @@ PublicationVolume <- function(
 #'
 #' @name Quote
 #' @param content The content that is marked. \bold{Required}.
-#' @param citation The source of the quote.
+#' @param cite The source of the quote.
 #' @param id The identifier for this item.
 #' @param meta Metadata associated with this item.
 #' @seealso \code{\link{Mark}}
 #' @export
 Quote <- function(
   content,
-  citation,
+  cite,
   id,
   meta
 ){
@@ -2208,7 +2265,7 @@ Quote <- function(
     meta = meta
   )
   self$type <- as_scalar("Quote")
-  self[["citation"]] <- check_property("Quote", "citation", FALSE, missing(citation), "character", citation)
+  self[["cite"]] <- check_property("Quote", "cite", FALSE, missing(cite), Union("Cite", "character"), cite)
   class(self) <- c("list", "Entity")
   self
 }
@@ -2218,14 +2275,14 @@ Quote <- function(
 #'
 #' @name QuoteBlock
 #' @param content The content of the quote. \bold{Required}.
-#' @param citation The source of the quote
+#' @param cite The source of the quote.
 #' @param id The identifier for this item.
 #' @param meta Metadata associated with this item.
 #' @seealso \code{\link{Entity}}
 #' @export
 QuoteBlock <- function(
   content,
-  citation,
+  cite,
   id,
   meta
 ){
@@ -2235,7 +2292,7 @@ QuoteBlock <- function(
   )
   self$type <- as_scalar("QuoteBlock")
   self[["content"]] <- check_property("QuoteBlock", "content", TRUE, missing(content), Array("BlockContent"), content)
-  self[["citation"]] <- check_property("QuoteBlock", "citation", FALSE, missing(citation), "character", citation)
+  self[["cite"]] <- check_property("QuoteBlock", "cite", FALSE, missing(cite), Union("Cite", "character"), cite)
   class(self) <- c("list", "Entity")
   self
 }
@@ -2294,6 +2351,7 @@ ResourceParameters <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -2320,6 +2378,7 @@ SoftwareApplication <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -2345,6 +2404,7 @@ SoftwareApplication <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -2425,6 +2485,7 @@ SoftwareSession <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param maintainers The people or organizations who maintain the software.
 #' @param meta Metadata associated with this item.
@@ -2456,6 +2517,7 @@ SoftwareSourceCode <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   maintainers,
   meta,
@@ -2484,6 +2546,7 @@ SoftwareSourceCode <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -2628,6 +2691,7 @@ Superscript <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -2653,6 +2717,7 @@ Table <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -2676,6 +2741,7 @@ Table <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
@@ -2698,9 +2764,9 @@ Table <- function(
 #'
 #' @name TableCell
 #' @param content Contents of the table cell. \bold{Required}.
+#' @param cellType Indicates whether the cell is a header or data.
 #' @param colspan How many columns the cell extends.
 #' @param id The identifier for this item.
-#' @param kind Indicates whether the cell is a header.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the cell.
 #' @param rowspan How many columns the cell extends.
@@ -2708,9 +2774,9 @@ Table <- function(
 #' @export
 TableCell <- function(
   content,
+  cellType,
   colspan,
   id,
-  kind,
   meta,
   name,
   rowspan
@@ -2721,8 +2787,8 @@ TableCell <- function(
   )
   self$type <- as_scalar("TableCell")
   self[["content"]] <- check_property("TableCell", "content", TRUE, missing(content), Array("InlineContent"), content)
+  self[["cellType"]] <- check_property("TableCell", "cellType", FALSE, missing(cellType), Enum("data", "header"), cellType)
   self[["colspan"]] <- check_property("TableCell", "colspan", FALSE, missing(colspan), "numeric", colspan)
-  self[["kind"]] <- check_property("TableCell", "kind", FALSE, missing(kind), Enum("data", "header"), kind)
   self[["name"]] <- check_property("TableCell", "name", FALSE, missing(name), "character", name)
   self[["rowspan"]] <- check_property("TableCell", "rowspan", FALSE, missing(rowspan), "numeric", rowspan)
   class(self) <- c("list", "Entity")
@@ -2735,15 +2801,15 @@ TableCell <- function(
 #' @name TableRow
 #' @param cells An array of cells in the row. \bold{Required}.
 #' @param id The identifier for this item.
-#' @param kind If present, indicates that all cells in this row should be treated as header cells.
 #' @param meta Metadata associated with this item.
+#' @param rowType If present, indicates that all cells in this row should be treated as header cells.
 #' @seealso \code{\link{Entity}}
 #' @export
 TableRow <- function(
   cells,
   id,
-  kind,
-  meta
+  meta,
+  rowType
 ){
   self <- Entity(
     id = id,
@@ -2751,7 +2817,7 @@ TableRow <- function(
   )
   self$type <- as_scalar("TableRow")
   self[["cells"]] <- check_property("TableRow", "cells", TRUE, missing(cells), Array("TableCell"), cells)
-  self[["kind"]] <- check_property("TableRow", "kind", FALSE, missing(kind), Enum("header", "footer"), kind)
+  self[["rowType"]] <- check_property("TableRow", "rowType", FALSE, missing(rowType), Enum("header", "footer"), rowType)
   class(self) <- c("list", "Entity")
   self
 }
@@ -2823,6 +2889,7 @@ TupleSchema <- function(
 #' @param funders Person or organisation that funded the CreativeWork.
 #' @param id The identifier for this item.
 #' @param isPartOf An item or other CreativeWork that this CreativeWork is a part of.
+#' @param keywords Keywords or tags used to describe this content. Multiple entries in a keywords list are typically delimited by commas.
 #' @param licenses License documents that applies to this content, typically indicated by URL.
 #' @param meta Metadata associated with this item.
 #' @param name The name of the item.
@@ -2855,6 +2922,7 @@ VideoObject <- function(
   funders,
   id,
   isPartOf,
+  keywords,
   licenses,
   meta,
   name,
@@ -2885,6 +2953,7 @@ VideoObject <- function(
     funders = funders,
     id = id,
     isPartOf = isPartOf,
+    keywords = keywords,
     licenses = licenses,
     meta = meta,
     name = name,
diff --git a/schema/ArraySchema.schema.yaml b/schema/ArraySchema.schema.yaml
index 21056fbf..7b8bb74a 100644
--- a/schema/ArraySchema.schema.yaml
+++ b/schema/ArraySchema.schema.yaml
@@ -7,7 +7,7 @@ category: data
 description: A schema specifying constraints on an array node.
 properties:
   items:
-    '@id': stencila:items
+    '@id': schema:itemListElement
     description: Another data schema node specifying the constraints on all items in the array.
     allOf:
       - $ref: SchemaTypes
diff --git a/schema/NumberSchema.schema.yaml b/schema/NumberSchema.schema.yaml
index 35b37492..5adbde47 100644
--- a/schema/NumberSchema.schema.yaml
+++ b/schema/NumberSchema.schema.yaml
@@ -27,7 +27,7 @@ properties:
       A number is valid against the schema only if it has a value greater
       than (not equal to) `exclusiveMinimum`.
   maximum:
-    '@id': stencila:exclusiveMaximum
+    '@id': stencila:maximum
     type: number
     description: The inclusive upper limit for a numeric node.
     $comment: |
diff --git a/schema/TupleSchema.schema.yaml b/schema/TupleSchema.schema.yaml
index d19f462f..0ef8457e 100644
--- a/schema/TupleSchema.schema.yaml
+++ b/schema/TupleSchema.schema.yaml
@@ -7,7 +7,7 @@ category: data
 description: A schema specifying constraints on an array of heterogeneous items.
 properties:
   items:
-    '@id': stencila:items
+    '@id': schema:itemListElement
     description: An array of schemas specifying the constraints on each successive item in the array.
     type: array
     items:
diff --git a/ts/interpreter.ts b/ts/interpreter.ts
index 2850f098..5e210cee 100644
--- a/ts/interpreter.ts
+++ b/ts/interpreter.ts
@@ -162,7 +162,7 @@ export function parseItem(
       parameters.push(item)
     } else if (
       (isA('CodeChunk', item) || isA('CodeExpression', item)) &&
-      item.language === 'javascript'
+      item.programmingLanguage === 'javascript'
     ) {
       if (isA('CodeChunk', item)) {
         const parseResult = parseCodeChunk(item)
diff --git a/ts/parsing.test.ts b/ts/parsing.test.ts
index 9e042a67..02b66475 100644
--- a/ts/parsing.test.ts
+++ b/ts/parsing.test.ts
@@ -265,22 +265,22 @@ describe('Parsing information from an Article', () => {
       {
         type: 'CodeChunk',
         text: "def a():\n    return 'I am python!'",
-        language: 'notjavascript'
+        programmingLanguage: 'notjavascript'
       },
       {
         type: 'CodeChunk',
         text: chunk1Text,
-        language: 'javascript'
+        programmingLanguage: 'javascript'
       },
       {
         type: 'CodeChunk',
         text: chunk2Text,
-        language: 'javascript'
+        programmingLanguage: 'javascript'
       },
       {
         type: 'CodeChunk',
         text: chunk3Text,
-        language: 'javascript',
+        programmingLanguage: 'javascript',
         declares: [
           {
             type: 'Function',
@@ -298,17 +298,17 @@ describe('Parsing information from an Article', () => {
       {
         type: 'CodeExpression',
         text: 'invalid code',
-        language: 'notjavascript'
+        programmingLanguage: 'notjavascript'
       },
       {
         type: 'CodeExpression',
         text: expr1Text,
-        language: 'javascript'
+        programmingLanguage: 'javascript'
       },
       {
         type: 'CodeExpression',
         text: expr2Text,
-        language: 'javascript'
+        programmingLanguage: 'javascript'
       }
     ]
   }
@@ -327,18 +327,22 @@ describe('Parsing information from an Article', () => {
     expect((code[3] as CodeExpression).text).toEqual(expr1Text)
     expect((code[4] as CodeExpression).text).toEqual(expr2Text)
 
-    expect((code[0] as CodeChunkExecution).codeChunk.language).toEqual(
+    expect(
+      (code[0] as CodeChunkExecution).codeChunk.programmingLanguage
+    ).toEqual('javascript')
+    expect(
+      (code[1] as CodeChunkExecution).codeChunk.programmingLanguage
+    ).toEqual('javascript')
+    expect(
+      (code[2] as CodeChunkExecution).codeChunk.programmingLanguage
+    ).toEqual('javascript')
+
+    expect((code[3] as CodeExpression).programmingLanguage).toEqual(
       'javascript'
     )
-    expect((code[1] as CodeChunkExecution).codeChunk.language).toEqual(
+    expect((code[4] as CodeExpression).programmingLanguage).toEqual(
       'javascript'
     )
-    expect((code[2] as CodeChunkExecution).codeChunk.language).toEqual(
-      'javascript'
-    )
-
-    expect((code[3] as CodeExpression).language).toEqual('javascript')
-    expect((code[4] as CodeExpression).language).toEqual('javascript')
   })
 
   test('it only parses Parameters that are not inside a Function', () => {
@@ -353,7 +357,7 @@ describe('Parsing information from an Article', () => {
     const c = codeChunk(
       "import { export1 } from 'module-name3'\nimport { export2 } from 'module-name4'",
       {
-        language: 'javascript',
+        programmingLanguage: 'javascript',
         imports: ['module-name1', 'module-name2', 'module-name3']
       }
     )
@@ -369,7 +373,10 @@ describe('Parsing information from an Article', () => {
   test("it doesn't add imports it finds to existing CodeChunk imports if the empty string semaphore is present", () => {
     const c = codeChunk(
       "import { export1 } from 'module-name3'\nimport { export2 } from 'module-name4'",
-      { language: 'javascript', imports: ['module-name1', 'module-name2', ''] }
+      {
+        programmingLanguage: 'javascript',
+        imports: ['module-name1', 'module-name2', '']
+      }
     )
     parseItem(c, [], [])