diff --git a/RDFSharp.Test/Model/RDFDatatypeRegisterTest.cs b/RDFSharp.Test/Model/Registers/RDFDatatypeRegisterTest.cs
similarity index 99%
rename from RDFSharp.Test/Model/RDFDatatypeRegisterTest.cs
rename to RDFSharp.Test/Model/Registers/RDFDatatypeRegisterTest.cs
index 1e45c3de..3cd748a1 100644
--- a/RDFSharp.Test/Model/RDFDatatypeRegisterTest.cs
+++ b/RDFSharp.Test/Model/Registers/RDFDatatypeRegisterTest.cs
@@ -18,7 +18,6 @@ limitations under the License.
 using RDFSharp.Model;
 using System;
 using System.Collections.Generic;
-using System.Linq;
 
 namespace RDFSharp.Test.Model
 {
diff --git a/RDFSharp.Test/Model/RDFNamespaceRegisterTest.cs b/RDFSharp.Test/Model/Registers/RDFNamespaceRegisterTest.cs
similarity index 100%
rename from RDFSharp.Test/Model/RDFNamespaceRegisterTest.cs
rename to RDFSharp.Test/Model/Registers/RDFNamespaceRegisterTest.cs
diff --git a/RDFSharp/Model/RDFDatatypeRegister.cs b/RDFSharp/Model/Registers/RDFDatatypeRegister.cs
similarity index 97%
rename from RDFSharp/Model/RDFDatatypeRegister.cs
rename to RDFSharp/Model/Registers/RDFDatatypeRegister.cs
index 1294f918..efe41dee 100644
--- a/RDFSharp/Model/RDFDatatypeRegister.cs
+++ b/RDFSharp/Model/Registers/RDFDatatypeRegister.cs
@@ -1,108 +1,108 @@
-/*
-   Copyright 2012-2025 Marco De Salvo
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-     http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-*/
-
-using System;
-using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
-
-namespace RDFSharp.Model
-{
-    /// <summary>
-    /// RDFDatatypeRegister is a singleton in-memory container for registered RDF datatypes
-    /// </summary>
-    public sealed class RDFDatatypeRegister : IEnumerable<RDFDatatype>
-    {
-        #region Statics
-        internal static RDFDatatype RDFSLiteral = new RDFDatatype(RDFVocabulary.RDFS.LITERAL.URI, RDFModelEnums.RDFDatatypes.RDFS_LITERAL, null);
-        #endregion
-
-        #region Properties
-        /// <summary>
-        /// Singleton instance of the RDFDatatypeRegister class
-        /// </summary>
-        public static RDFDatatypeRegister Instance { get; internal set; }
-
-        /// <summary>
-        /// List of registered datatypes
-        /// </summary>
-        internal List<RDFDatatype> Register { get; set; }
-
-        /// <summary>
-        /// Count of the register's namespaces
-        /// </summary>
-        public static int DatatypesCount
-            => Instance.Register.Count;
-
-        /// <summary>
-        /// Gets the enumerator on the register's namespaces for iteration
-        /// </summary>
-        public static IEnumerator<RDFDatatype> DatatypesEnumerator
-            => Instance.Register.GetEnumerator();
-        #endregion
-
-        #region Ctors
-        /// <summary>
-        /// Default-ctor to initialize the singleton instance of the register
-        /// </summary>
-        static RDFDatatypeRegister()
-        {
-            Instance = new RDFDatatypeRegister { 
-                Register = new List<RDFDatatype>() };
-
-            foreach (RDFModelEnums.RDFDatatypes datatype in Enum.GetValues(typeof(RDFModelEnums.RDFDatatypes)).Cast<RDFModelEnums.RDFDatatypes>())
-                Instance.Register.Add(new RDFDatatype(new Uri(RDFModelUtilities.GetDatatypeFromEnum(datatype)), datatype, null) { IsBuiltIn = true });
-        }
-        #endregion
-
-        #region Interfaces
-        /// <summary>
-        /// Exposes a typed enumerator on the register's datatypes
-        /// </summary>
-        IEnumerator<RDFDatatype> IEnumerable<RDFDatatype>.GetEnumerator()
-            => DatatypesEnumerator;
-
-        /// <summary>
-        /// Exposes an untyped enumerator on the register's datatypes
-        /// </summary>
-        IEnumerator IEnumerable.GetEnumerator()
-            => DatatypesEnumerator;
-        #endregion
-
-        #region Methods
-        /// <summary>
-        /// Adds the given datatype to the register
-        /// </summary>
-        public static void AddDatatype(RDFDatatype datatype)
-        {
-            if (datatype != null && GetDatatype(datatype.ToString()) == null)
-                Instance.Register.Add(datatype);
-        }
-
-        /// <summary>
-        /// Retrieves a standard datatype by seeking presence of its Uri
-        /// </summary>
-        public static RDFDatatype GetDatatype(RDFModelEnums.RDFDatatypes datatype)
-            => GetDatatype(datatype.GetDatatypeFromEnum());
-
-        /// <summary>
-        /// Retrieves a datatype by seeking presence of its Uri (null if not found)
-        /// </summary>
-        public static RDFDatatype GetDatatype(string datatypeUri)
-            => Instance.Register.Find(dt => string.Equals(dt.ToString(), datatypeUri?.Trim()));
-        #endregion
-    }
+/*
+   Copyright 2012-2025 Marco De Salvo
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace RDFSharp.Model
+{
+    /// <summary>
+    /// RDFDatatypeRegister is a singleton in-memory container for registered RDF datatypes
+    /// </summary>
+    public sealed class RDFDatatypeRegister : IEnumerable<RDFDatatype>
+    {
+        #region Statics
+        internal static RDFDatatype RDFSLiteral = new RDFDatatype(RDFVocabulary.RDFS.LITERAL.URI, RDFModelEnums.RDFDatatypes.RDFS_LITERAL, null);
+        #endregion
+
+        #region Properties
+        /// <summary>
+        /// Singleton instance of the RDFDatatypeRegister class
+        /// </summary>
+        public static RDFDatatypeRegister Instance { get; internal set; }
+
+        /// <summary>
+        /// List of registered datatypes
+        /// </summary>
+        internal List<RDFDatatype> Register { get; set; }
+
+        /// <summary>
+        /// Count of the register's namespaces
+        /// </summary>
+        public static int DatatypesCount
+            => Instance.Register.Count;
+
+        /// <summary>
+        /// Gets the enumerator on the register's namespaces for iteration
+        /// </summary>
+        public static IEnumerator<RDFDatatype> DatatypesEnumerator
+            => Instance.Register.GetEnumerator();
+        #endregion
+
+        #region Ctors
+        /// <summary>
+        /// Default-ctor to initialize the singleton instance of the register
+        /// </summary>
+        static RDFDatatypeRegister()
+        {
+            Instance = new RDFDatatypeRegister { 
+                Register = new List<RDFDatatype>() };
+
+            foreach (RDFModelEnums.RDFDatatypes datatype in Enum.GetValues(typeof(RDFModelEnums.RDFDatatypes)).Cast<RDFModelEnums.RDFDatatypes>())
+                Instance.Register.Add(new RDFDatatype(new Uri(RDFModelUtilities.GetDatatypeFromEnum(datatype)), datatype, null) { IsBuiltIn = true });
+        }
+        #endregion
+
+        #region Interfaces
+        /// <summary>
+        /// Exposes a typed enumerator on the register's datatypes
+        /// </summary>
+        IEnumerator<RDFDatatype> IEnumerable<RDFDatatype>.GetEnumerator()
+            => DatatypesEnumerator;
+
+        /// <summary>
+        /// Exposes an untyped enumerator on the register's datatypes
+        /// </summary>
+        IEnumerator IEnumerable.GetEnumerator()
+            => DatatypesEnumerator;
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// Adds the given datatype to the register
+        /// </summary>
+        public static void AddDatatype(RDFDatatype datatype)
+        {
+            if (datatype != null && GetDatatype(datatype.ToString()) == null)
+                Instance.Register.Add(datatype);
+        }
+
+        /// <summary>
+        /// Retrieves a standard datatype by seeking presence of its Uri
+        /// </summary>
+        public static RDFDatatype GetDatatype(RDFModelEnums.RDFDatatypes datatype)
+            => GetDatatype(datatype.GetDatatypeFromEnum());
+
+        /// <summary>
+        /// Retrieves a datatype by seeking presence of its Uri (null if not found)
+        /// </summary>
+        public static RDFDatatype GetDatatype(string datatypeUri)
+            => Instance.Register.Find(dt => string.Equals(dt.ToString(), datatypeUri?.Trim()));
+        #endregion
+    }
 }
\ No newline at end of file
diff --git a/RDFSharp/Model/RDFNamespaceRegister.cs b/RDFSharp/Model/Registers/RDFNamespaceRegister.cs
similarity index 97%
rename from RDFSharp/Model/RDFNamespaceRegister.cs
rename to RDFSharp/Model/Registers/RDFNamespaceRegister.cs
index d0ebc253..f0becd32 100644
--- a/RDFSharp/Model/RDFNamespaceRegister.cs
+++ b/RDFSharp/Model/Registers/RDFNamespaceRegister.cs
@@ -1,237 +1,237 @@
-/*
-   Copyright 2012-2025 Marco De Salvo
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-     http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-*/
-
-using System;
-using System.Collections;
-using System.Collections.Generic;
-using static RDFSharp.Query.RDFQueryUtilities;
-
-namespace RDFSharp.Model
-{
-    /// <summary>
-    /// RDFNamespaceRegister is a singleton in-memory container for registered RDF namespaces.
-    /// </summary>
-    public sealed class RDFNamespaceRegister : IEnumerable<RDFNamespace>
-    {
-        #region Properties
-        /// <summary>
-        /// Default namespace of the library (rdfsharp)
-        /// </summary>
-        private static readonly RDFNamespace RDFSharpNS = new RDFNamespace(RDFVocabulary.RDFSHARP.PREFIX, RDFVocabulary.RDFSHARP.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.RDFSHARP.DEREFERENCE_URI));
-
-        /// <summary>
-        /// Default namespace of the library
-        /// </summary>
-        public static RDFNamespace DefaultNamespace { get; internal set; }
-
-        /// <summary>
-        /// Singleton instance of the RDFNamespaceRegister class
-        /// </summary>
-        public static RDFNamespaceRegister Instance { get; internal set; }
-
-        /// <summary>
-        /// List of registered namespaces
-        /// </summary>
-        internal List<RDFNamespace> Register { get; set; }
-
-        /// <summary>
-        /// Count of the register's namespaces
-        /// </summary>
-        public static int NamespacesCount
-            => Instance.Register.Count;
-
-        /// <summary>
-        /// Gets the enumerator on the register's namespaces for iteration
-        /// </summary>
-        public static IEnumerator<RDFNamespace> NamespacesEnumerator
-            => Instance.Register.GetEnumerator();
-        #endregion
-
-        #region Ctors
-        /// <summary>
-        /// Default-ctor to initialize the singleton instance of the register
-        /// </summary>
-        static RDFNamespaceRegister()
-        {
-            Instance = new RDFNamespaceRegister()
-            {
-                Register = new List<RDFNamespace>()
-                {
-                    RDFSharpNS,
-
-                    //Basic
-                    new RDFNamespace(RDFVocabulary.RDF.PREFIX, RDFVocabulary.RDF.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.RDF.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.RDFS.PREFIX, RDFVocabulary.RDFS.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.RDFS.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.XSD.PREFIX, RDFVocabulary.XSD.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.XSD.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.OWL.PREFIX, RDFVocabulary.OWL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.OWL.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.SHACL.PREFIX, RDFVocabulary.SHACL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SHACL.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.SWRL.PREFIX, RDFVocabulary.SWRL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SWRL.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.SWRL.SWRLB.PREFIX, RDFVocabulary.SWRL.SWRLB.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SWRL.SWRLB.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.XML.PREFIX, RDFVocabulary.XML.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.XML.DEREFERENCE_URI)),
-
-                    //Extended
-                    new RDFNamespace(RDFVocabulary.DC.PREFIX, RDFVocabulary.DC.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.DC.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.DC.DCAM.PREFIX, RDFVocabulary.DC.DCAM.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.DC.DCAM.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.DC.DCTERMS.PREFIX, RDFVocabulary.DC.DCTERMS.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.DC.DCTERMS.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.DC.DCTYPE.PREFIX, RDFVocabulary.DC.DCTYPE.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.DC.DCTYPE.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.FOAF.PREFIX, RDFVocabulary.FOAF.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.FOAF.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.GEO.PREFIX, RDFVocabulary.GEO.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.GEO.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.GEOSPARQL.PREFIX, RDFVocabulary.GEOSPARQL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.GEOSPARQL.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.GEOSPARQL.SF.PREFIX, RDFVocabulary.GEOSPARQL.SF.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.GEOSPARQL.SF.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.GEOSPARQL.GEOF.PREFIX, RDFVocabulary.GEOSPARQL.GEOF.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.GEOSPARQL.GEOF.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.SKOS.PREFIX, RDFVocabulary.SKOS.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SKOS.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.SKOS.SKOSXL.PREFIX, RDFVocabulary.SKOS.SKOSXL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SKOS.SKOSXL.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.TIME.PREFIX, RDFVocabulary.TIME.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.TIME.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.TIME.GREG.PREFIX, RDFVocabulary.TIME.GREG.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.TIME.GREG.DEREFERENCE_URI)),
-                    new RDFNamespace(RDFVocabulary.TIME.THORS.PREFIX, RDFVocabulary.TIME.THORS.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.TIME.THORS.DEREFERENCE_URI))
-                }
-            };
-
-            DefaultNamespace = RDFSharpNS;
-        }
-        #endregion
-
-        #region Interfaces
-        /// <summary>
-        /// Exposes a typed enumerator on the register's namespaces
-        /// </summary>
-        IEnumerator<RDFNamespace> IEnumerable<RDFNamespace>.GetEnumerator()
-            => NamespacesEnumerator;
-
-        /// <summary>
-        /// Exposes an untyped enumerator on the register's namespaces
-        /// </summary>
-        IEnumerator IEnumerable.GetEnumerator()
-            => NamespacesEnumerator;
-        #endregion
-
-        #region Methods
-        /// <summary>
-        /// Sets the given namespace as default namespace of the library.
-        /// </summary>
-        public static void SetDefaultNamespace(RDFNamespace nSpace)
-        {
-            if (nSpace != null)
-            {
-                DefaultNamespace = nSpace;
-
-                //Also add it to the register
-                AddNamespace(nSpace);
-            }
-        }
-
-        /// <summary>
-        /// Resets the default namespace of the library.
-        /// </summary>
-        public static void ResetDefaultNamespace()
-            => DefaultNamespace = RDFSharpNS;
-
-        /// <summary>
-        /// Adds the given namespace to the register, if it has unique prefix and uri.
-        /// </summary>
-        public static void AddNamespace(RDFNamespace nSpace)
-        {
-            if (nSpace != null)
-            {
-                if (GetByPrefix(nSpace.NamespacePrefix) == null && GetByUri(nSpace.NamespaceUri.ToString()) == null)
-                    Instance.Register.Add(nSpace);
-            }
-        }
-
-        /// <summary>
-        /// Removes the namespace having the given Uri.
-        /// </summary>
-        public static void RemoveByUri(string uri)
-        {
-            if (uri != null)
-                Instance.Register.RemoveAll(ns => string.Equals(ns.NamespaceUri.ToString(), uri.Trim(), StringComparison.OrdinalIgnoreCase));
-        }
-
-        /// <summary>
-        /// Removes the namespace having the given prefix.
-        /// </summary>
-        public static void RemoveByPrefix(string prefix)
-        {
-            if (prefix != null)
-                Instance.Register.RemoveAll(ns => string.Equals(ns.NamespacePrefix, prefix.Trim(), StringComparison.OrdinalIgnoreCase));
-        }
-
-        /// <summary>
-        /// Retrieves a namespace by seeking presence of its Uri (cascading a lookup to prefix.cc service, if specified)
-        /// </summary>
-        public static RDFNamespace GetByUri(string uri, bool enablePrefixCCService = false)
-        {
-            if (uri != null)
-            {
-                RDFNamespace result = Instance.Register.Find(ns => string.Equals(ns.NamespaceUri.ToString(), uri.Trim(), StringComparison.OrdinalIgnoreCase));
-                if (result == null && enablePrefixCCService)
-                    result = LookupPrefixCC(uri.Trim().TrimEnd(new char[] { '#' }), 2);
-                return result;
-            }
-            return null;
-        }
-
-        /// <summary>
-        /// Retrieves a namespace by seeking presence of its prefix (cascading a lookup to prefix.cc service, if specified)
-        /// </summary>
-        public static RDFNamespace GetByPrefix(string prefix, bool enablePrefixCCService = false)
-        {
-            if (prefix != null)
-            {
-                RDFNamespace result = Instance.Register.Find(ns => string.Equals(ns.NamespacePrefix, prefix.Trim(), StringComparison.OrdinalIgnoreCase));
-                if (result == null && enablePrefixCCService)
-                    result = LookupPrefixCC(prefix.Trim(), 1);
-                return result;
-            }
-            return null;
-        }
-
-        /// <summary>
-        /// Lookups the given prefix or namespace into the prefix.cc service
-        /// </summary>
-        internal static RDFNamespace LookupPrefixCC(string data, int lookupMode)
-        {
-            string lookupString = lookupMode == 1 ? string.Concat("http://prefix.cc/", data, ".file.txt")
-                                                  : string.Concat("http://prefix.cc/reverse?uri=", data, "&format=txt");
-
-            using (RDFWebClient webclient = new RDFWebClient(1000))
-            {
-                try
-                {
-                    string response = webclient.DownloadString(lookupString);
-                    string[] splittedResponse = response.Split('\t');
-                    string prefix = splittedResponse[0];
-                    string nspace = splittedResponse[1].TrimEnd(Environment.NewLine);
-                    RDFNamespace result = new RDFNamespace(prefix, nspace);
-
-                    //Also add the namespace to the register (to avoid future lookups)
-                    AddNamespace(result);
-
-                    //Return the found result
-                    return result;
-                }
-                catch { return null; }
-            }
-        }
-
-        /// <summary>
-        /// Removes namespaces marked as temporary
-        /// </summary>
-        internal static void RemoveTemporaryNamespaces()
-            => Instance.Register.RemoveAll(x => x.IsTemporary);
-        #endregion
-    }
+/*
+   Copyright 2012-2025 Marco De Salvo
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using static RDFSharp.Query.RDFQueryUtilities;
+
+namespace RDFSharp.Model
+{
+    /// <summary>
+    /// RDFNamespaceRegister is a singleton in-memory container for registered RDF namespaces.
+    /// </summary>
+    public sealed class RDFNamespaceRegister : IEnumerable<RDFNamespace>
+    {
+        #region Properties
+        /// <summary>
+        /// Default namespace of the library (rdfsharp)
+        /// </summary>
+        private static readonly RDFNamespace RDFSharpNS = new RDFNamespace(RDFVocabulary.RDFSHARP.PREFIX, RDFVocabulary.RDFSHARP.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.RDFSHARP.DEREFERENCE_URI));
+
+        /// <summary>
+        /// Default namespace of the library
+        /// </summary>
+        public static RDFNamespace DefaultNamespace { get; internal set; }
+
+        /// <summary>
+        /// Singleton instance of the RDFNamespaceRegister class
+        /// </summary>
+        public static RDFNamespaceRegister Instance { get; internal set; }
+
+        /// <summary>
+        /// List of registered namespaces
+        /// </summary>
+        internal List<RDFNamespace> Register { get; set; }
+
+        /// <summary>
+        /// Count of the register's namespaces
+        /// </summary>
+        public static int NamespacesCount
+            => Instance.Register.Count;
+
+        /// <summary>
+        /// Gets the enumerator on the register's namespaces for iteration
+        /// </summary>
+        public static IEnumerator<RDFNamespace> NamespacesEnumerator
+            => Instance.Register.GetEnumerator();
+        #endregion
+
+        #region Ctors
+        /// <summary>
+        /// Default-ctor to initialize the singleton instance of the register
+        /// </summary>
+        static RDFNamespaceRegister()
+        {
+            Instance = new RDFNamespaceRegister()
+            {
+                Register = new List<RDFNamespace>()
+                {
+                    RDFSharpNS,
+
+                    //Basic
+                    new RDFNamespace(RDFVocabulary.RDF.PREFIX, RDFVocabulary.RDF.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.RDF.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.RDFS.PREFIX, RDFVocabulary.RDFS.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.RDFS.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.XSD.PREFIX, RDFVocabulary.XSD.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.XSD.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.OWL.PREFIX, RDFVocabulary.OWL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.OWL.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.SHACL.PREFIX, RDFVocabulary.SHACL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SHACL.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.SWRL.PREFIX, RDFVocabulary.SWRL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SWRL.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.SWRL.SWRLB.PREFIX, RDFVocabulary.SWRL.SWRLB.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SWRL.SWRLB.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.XML.PREFIX, RDFVocabulary.XML.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.XML.DEREFERENCE_URI)),
+
+                    //Extended
+                    new RDFNamespace(RDFVocabulary.DC.PREFIX, RDFVocabulary.DC.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.DC.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.DC.DCAM.PREFIX, RDFVocabulary.DC.DCAM.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.DC.DCAM.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.DC.DCTERMS.PREFIX, RDFVocabulary.DC.DCTERMS.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.DC.DCTERMS.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.DC.DCTYPE.PREFIX, RDFVocabulary.DC.DCTYPE.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.DC.DCTYPE.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.FOAF.PREFIX, RDFVocabulary.FOAF.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.FOAF.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.GEO.PREFIX, RDFVocabulary.GEO.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.GEO.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.GEOSPARQL.PREFIX, RDFVocabulary.GEOSPARQL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.GEOSPARQL.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.GEOSPARQL.SF.PREFIX, RDFVocabulary.GEOSPARQL.SF.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.GEOSPARQL.SF.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.GEOSPARQL.GEOF.PREFIX, RDFVocabulary.GEOSPARQL.GEOF.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.GEOSPARQL.GEOF.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.SKOS.PREFIX, RDFVocabulary.SKOS.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SKOS.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.SKOS.SKOSXL.PREFIX, RDFVocabulary.SKOS.SKOSXL.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.SKOS.SKOSXL.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.TIME.PREFIX, RDFVocabulary.TIME.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.TIME.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.TIME.GREG.PREFIX, RDFVocabulary.TIME.GREG.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.TIME.GREG.DEREFERENCE_URI)),
+                    new RDFNamespace(RDFVocabulary.TIME.THORS.PREFIX, RDFVocabulary.TIME.THORS.BASE_URI).SetDereferenceUri(new Uri(RDFVocabulary.TIME.THORS.DEREFERENCE_URI))
+                }
+            };
+
+            DefaultNamespace = RDFSharpNS;
+        }
+        #endregion
+
+        #region Interfaces
+        /// <summary>
+        /// Exposes a typed enumerator on the register's namespaces
+        /// </summary>
+        IEnumerator<RDFNamespace> IEnumerable<RDFNamespace>.GetEnumerator()
+            => NamespacesEnumerator;
+
+        /// <summary>
+        /// Exposes an untyped enumerator on the register's namespaces
+        /// </summary>
+        IEnumerator IEnumerable.GetEnumerator()
+            => NamespacesEnumerator;
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// Sets the given namespace as default namespace of the library.
+        /// </summary>
+        public static void SetDefaultNamespace(RDFNamespace nSpace)
+        {
+            if (nSpace != null)
+            {
+                DefaultNamespace = nSpace;
+
+                //Also add it to the register
+                AddNamespace(nSpace);
+            }
+        }
+
+        /// <summary>
+        /// Resets the default namespace of the library.
+        /// </summary>
+        public static void ResetDefaultNamespace()
+            => DefaultNamespace = RDFSharpNS;
+
+        /// <summary>
+        /// Adds the given namespace to the register, if it has unique prefix and uri.
+        /// </summary>
+        public static void AddNamespace(RDFNamespace nSpace)
+        {
+            if (nSpace != null)
+            {
+                if (GetByPrefix(nSpace.NamespacePrefix) == null && GetByUri(nSpace.NamespaceUri.ToString()) == null)
+                    Instance.Register.Add(nSpace);
+            }
+        }
+
+        /// <summary>
+        /// Removes the namespace having the given Uri.
+        /// </summary>
+        public static void RemoveByUri(string uri)
+        {
+            if (uri != null)
+                Instance.Register.RemoveAll(ns => string.Equals(ns.NamespaceUri.ToString(), uri.Trim(), StringComparison.OrdinalIgnoreCase));
+        }
+
+        /// <summary>
+        /// Removes the namespace having the given prefix.
+        /// </summary>
+        public static void RemoveByPrefix(string prefix)
+        {
+            if (prefix != null)
+                Instance.Register.RemoveAll(ns => string.Equals(ns.NamespacePrefix, prefix.Trim(), StringComparison.OrdinalIgnoreCase));
+        }
+
+        /// <summary>
+        /// Retrieves a namespace by seeking presence of its Uri (cascading a lookup to prefix.cc service, if specified)
+        /// </summary>
+        public static RDFNamespace GetByUri(string uri, bool enablePrefixCCService = false)
+        {
+            if (uri != null)
+            {
+                RDFNamespace result = Instance.Register.Find(ns => string.Equals(ns.NamespaceUri.ToString(), uri.Trim(), StringComparison.OrdinalIgnoreCase));
+                if (result == null && enablePrefixCCService)
+                    result = LookupPrefixCC(uri.Trim().TrimEnd(new char[] { '#' }), 2);
+                return result;
+            }
+            return null;
+        }
+
+        /// <summary>
+        /// Retrieves a namespace by seeking presence of its prefix (cascading a lookup to prefix.cc service, if specified)
+        /// </summary>
+        public static RDFNamespace GetByPrefix(string prefix, bool enablePrefixCCService = false)
+        {
+            if (prefix != null)
+            {
+                RDFNamespace result = Instance.Register.Find(ns => string.Equals(ns.NamespacePrefix, prefix.Trim(), StringComparison.OrdinalIgnoreCase));
+                if (result == null && enablePrefixCCService)
+                    result = LookupPrefixCC(prefix.Trim(), 1);
+                return result;
+            }
+            return null;
+        }
+
+        /// <summary>
+        /// Lookups the given prefix or namespace into the prefix.cc service
+        /// </summary>
+        internal static RDFNamespace LookupPrefixCC(string data, int lookupMode)
+        {
+            string lookupString = lookupMode == 1 ? string.Concat("http://prefix.cc/", data, ".file.txt")
+                                                  : string.Concat("http://prefix.cc/reverse?uri=", data, "&format=txt");
+
+            using (RDFWebClient webclient = new RDFWebClient(1000))
+            {
+                try
+                {
+                    string response = webclient.DownloadString(lookupString);
+                    string[] splittedResponse = response.Split('\t');
+                    string prefix = splittedResponse[0];
+                    string nspace = splittedResponse[1].TrimEnd(Environment.NewLine);
+                    RDFNamespace result = new RDFNamespace(prefix, nspace);
+
+                    //Also add the namespace to the register (to avoid future lookups)
+                    AddNamespace(result);
+
+                    //Return the found result
+                    return result;
+                }
+                catch { return null; }
+            }
+        }
+
+        /// <summary>
+        /// Removes namespaces marked as temporary
+        /// </summary>
+        internal static void RemoveTemporaryNamespaces()
+            => Instance.Register.RemoveAll(x => x.IsTemporary);
+        #endregion
+    }
 }
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