diff --git a/py/stencila/schema/types.py b/py/stencila/schema/types.py
index 01c10c5b..bdbc97ee 100644
--- a/py/stencila/schema/types.py
+++ b/py/stencila/schema/types.py
@@ -619,7 +619,7 @@ class CreativeWork(Thing):
     etc.
     """
 
-    about: Optional[Array["Thing"]] = None
+    about: Optional[Array["ThingTypes"]] = None
     """The subject matter of the content."""
 
     authors: Optional[Array[Union["Person", "Organization"]]] = None
@@ -700,7 +700,7 @@ class CreativeWork(Thing):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         comments: Optional[Array["Comment"]] = None,
@@ -810,7 +810,7 @@ class Article(CreativeWork):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         comments: Optional[Array["Comment"]] = None,
@@ -903,7 +903,7 @@ class Claim(CreativeWork):
     def __init__(
         self,
         content: Array["BlockContent"],
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         claimType: Optional["EClaimType"] = None,
@@ -988,7 +988,7 @@ class Collection(CreativeWork):
     def __init__(
         self,
         parts: Array["CreativeWorkTypes"],
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         comments: Optional[Array["Comment"]] = None,
@@ -1068,7 +1068,7 @@ class Comment(CreativeWork):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         commentAspect: Optional[str] = None,
@@ -1151,7 +1151,7 @@ class Datatable(CreativeWork):
     def __init__(
         self,
         columns: Array["DatatableColumn"],
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         comments: Optional[Array["Comment"]] = None,
@@ -1250,7 +1250,7 @@ class MediaObject(CreativeWork):
     def __init__(
         self,
         contentUrl: str,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         bitrate: Optional[float] = None,
@@ -1344,7 +1344,7 @@ class AudioObject(MediaObject):
     def __init__(
         self,
         contentUrl: str,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         bitrate: Optional[float] = None,
@@ -1670,7 +1670,7 @@ class Figure(CreativeWork):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         caption: Optional[Union[Array["BlockContent"], str]] = None,
@@ -1858,7 +1858,7 @@ class ImageObject(MediaObject):
     def __init__(
         self,
         contentUrl: str,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         bitrate: Optional[float] = None,
@@ -2556,7 +2556,7 @@ class Periodical(CreativeWork):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         comments: Optional[Array["Comment"]] = None,
@@ -2906,7 +2906,7 @@ class PublicationIssue(CreativeWork):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         comments: Optional[Array["Comment"]] = None,
@@ -3009,7 +3009,7 @@ class PublicationVolume(CreativeWork):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         comments: Optional[Array["Comment"]] = None,
@@ -3150,7 +3150,7 @@ class Review(CreativeWork):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         comments: Optional[Array["Comment"]] = None,
@@ -3237,7 +3237,7 @@ class SoftwareApplication(CreativeWork):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         comments: Optional[Array["Comment"]] = None,
@@ -3526,7 +3526,7 @@ class SoftwareSourceCode(CreativeWork):
 
     def __init__(
         self,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         codeRepository: Optional[str] = None,
@@ -3712,7 +3712,7 @@ class Table(CreativeWork):
     def __init__(
         self,
         rows: Array["TableRow"],
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         caption: Optional[Union[Array["BlockContent"], str]] = None,
@@ -3918,7 +3918,7 @@ class VideoObject(MediaObject):
     def __init__(
         self,
         contentUrl: str,
-        about: Optional[Array["Thing"]] = None,
+        about: Optional[Array["ThingTypes"]] = None,
         alternateNames: Optional[Array[str]] = None,
         authors: Optional[Array[Union["Person", "Organization"]]] = None,
         bitrate: Optional[float] = None,
diff --git a/r/R/types.R b/r/R/types.R
index 2116f807..16122cf2 100644
--- a/r/R/types.R
+++ b/r/R/types.R
@@ -676,7 +676,7 @@ CreativeWork <- function(
     url = url
   )
   self$type <- as_scalar("CreativeWork")
-  self[["about"]] <- check_property("CreativeWork", "about", FALSE, missing(about), Array(Thing), about)
+  self[["about"]] <- check_property("CreativeWork", "about", FALSE, missing(about), Array(ThingTypes), about)
   self[["authors"]] <- check_property("CreativeWork", "authors", FALSE, missing(authors), Array(Union(Person, Organization)), authors)
   self[["comments"]] <- check_property("CreativeWork", "comments", FALSE, missing(comments), Array(Comment), comments)
   self[["content"]] <- check_property("CreativeWork", "content", FALSE, missing(content), Array(Node), content)
diff --git a/schema/CreativeWork.schema.yaml b/schema/CreativeWork.schema.yaml
index e60e8a23..50298c31 100644
--- a/schema/CreativeWork.schema.yaml
+++ b/schema/CreativeWork.schema.yaml
@@ -21,7 +21,7 @@ properties:
       subject areas the creative work relates to).
     type: array
     items:
-      $ref: Thing
+      $ref: ThingTypes
   authors:
     '@id': schema:author
     description: The authors of this creative work.