diff --git a/source/DefaultDocumentation/DefaultDocumentation.Release.csproj b/source/DefaultDocumentation/DefaultDocumentation.Release.csproj
index 3b5fd257..8e37f53a 100644
--- a/source/DefaultDocumentation/DefaultDocumentation.Release.csproj
+++ b/source/DefaultDocumentation/DefaultDocumentation.Release.csproj
@@ -7,9 +7,12 @@
   </PropertyGroup>
 
   <PropertyGroup Label="Package">
-    <Version>0.5.4</Version>
+    <Version>0.5.5</Version>
     <PackageReleaseNotes>
+fixed TypeDocItem writing members of nested types
 fixed nested type not showing parent type in name
+fixed NullReferenceException for generic type
+fixed internal interfaces shown in implementation
     </PackageReleaseNotes>
   </PropertyGroup>
 </Project>
\ No newline at end of file
diff --git a/source/DefaultDocumentation/DocumentationWriter.cs b/source/DefaultDocumentation/DocumentationWriter.cs
index 1bdaa0aa..41db4925 100644
--- a/source/DefaultDocumentation/DocumentationWriter.cs
+++ b/source/DefaultDocumentation/DocumentationWriter.cs
@@ -75,7 +75,8 @@ public string GetTypeLink(DocItem item, IType type)
         {
             string HandleParameterizedType(ParameterizedType genericType)
             {
-                if (_items.TryGetValue(genericType.GetDefinition().GetIdString(), out DocItem docItem) && docItem is TypeDocItem typeDocItem)
+                ITypeDefinition typeDefinition = genericType.GetDefinition();
+                if (typeDefinition != null && _items.TryGetValue(typeDefinition.GetIdString(), out DocItem docItem) && docItem is TypeDocItem typeDocItem)
                 {
                     return GetLink(docItem, typeDocItem.Type.FullName + "&lt;")
                         + string.Join(GetLink(docItem, ","), genericType.TypeArguments.Select(t => GetTypeLink(item, t)))
diff --git a/source/DefaultDocumentation/Model/TypeDocItem.cs b/source/DefaultDocumentation/Model/TypeDocItem.cs
index 4787cff4..a4621de5 100644
--- a/source/DefaultDocumentation/Model/TypeDocItem.cs
+++ b/source/DefaultDocumentation/Model/TypeDocItem.cs
@@ -44,7 +44,7 @@ public override void WriteDocumentation(DocumentationWriter writer)
 
             writer.Write(this, Documentation.GetSummary());
 
-            List<IType> interfaces = Type.DirectBaseTypes.Where(t => t.Kind == TypeKind.Interface).ToList();
+            List<IType> interfaces = Type.DirectBaseTypes.Where(t => t.Kind == TypeKind.Interface && t.GetDefinition().Accessibility == Accessibility.Public).ToList();
 
             writer.WriteLine("```csharp");
             writer.Write(CodeAmbience.ConvertSymbol(Type));
diff --git a/source/DefaultDocumentation/Properties/launchSettings.json b/source/DefaultDocumentation/Properties/launchSettings.json
index b899fb9d..2184af9a 100644
--- a/source/DefaultDocumentation/Properties/launchSettings.json
+++ b/source/DefaultDocumentation/Properties/launchSettings.json
@@ -2,7 +2,7 @@
   "profiles": {
     "DefaultDocumentation": {
       "commandName": "Project",
-      "commandLineArgs": "/assembly:\"D:\\Projects\\DefaultEcs\\source\\DefaultEcs\\bin\\Release\\netstandard2.0\\DefaultEcs.dll\" /xml:\"D:\\Projects\\DefaultEcs\\source\\DefaultEcs\\bin\\Release\\netstandard2.0\\DefaultEcs.xml\" /output:\"D:\\Projects\\DefaultEcs\\documentation\\api\""
+      "commandLineArgs": "/assembly:\"D:\\Projects\\DefaultEcs\\source\\DefaultEcs\\bin\\Release\\netstandard2.1\\DefaultEcs.dll\" /xml:\"D:\\Projects\\DefaultEcs\\source\\DefaultEcs\\obj\\Release\\netstandard2.1\\DefaultEcs.xml\" /output:\"D:\\Projects\\DefaultEcs\\documentation\\api\" /home:\"\" /baselink:\"\" /linksfile:\"\""
     }
   }
 }
\ No newline at end of file