diff --git a/src/Microsoft.DocAsCode.Build.ConceptualDocuments/ConceptualDocumentProcessor.cs b/src/Microsoft.DocAsCode.Build.ConceptualDocuments/ConceptualDocumentProcessor.cs
index f7bf9edf533..f3152febe35 100644
--- a/src/Microsoft.DocAsCode.Build.ConceptualDocuments/ConceptualDocumentProcessor.cs
+++ b/src/Microsoft.DocAsCode.Build.ConceptualDocuments/ConceptualDocumentProcessor.cs
@@ -106,8 +106,8 @@ public override SaveResult Save(FileModel model)
         {
             var properties = (IDictionary<string, object>)model.Content;
             documentType = properties.ContainsKey(Constants.PropertyName.RedirectUrl)
-              ? nameof(DocumentType.Redirection)
-              : "Conceptual";
+              ? Constants.DocumentType.Redirection
+              : Constants.DocumentType.Conceptual;
         }
 
         var result = new SaveResult
diff --git a/src/Microsoft.DocAsCode.Build.Engine/PostProcessors/SitemapGenerator.cs b/src/Microsoft.DocAsCode.Build.Engine/PostProcessors/SitemapGenerator.cs
index cf44895074d..1ea61945667 100644
--- a/src/Microsoft.DocAsCode.Build.Engine/PostProcessors/SitemapGenerator.cs
+++ b/src/Microsoft.DocAsCode.Build.Engine/PostProcessors/SitemapGenerator.cs
@@ -155,9 +155,11 @@ private static SitemapElementOptions GetMatchingOptions(SitemapOptions options,
         {
             switch (file.DocumentType)
             {
-                case "Toc":
-                case "Redirection":
-                    continue; // Skip non sitemap target files.
+                // Skip non sitemap target files.
+                case DataContracts.Common.Constants.DocumentType.Toc:
+                case DataContracts.Common.Constants.DocumentType.Redirection:
+                    continue;
+
                 default:
                     break;
             }
diff --git a/src/Microsoft.DocAsCode.DataContracts.Common/Constants.cs b/src/Microsoft.DocAsCode.DataContracts.Common/Constants.cs
index 55dea460953..e30a7dd61ac 100644
--- a/src/Microsoft.DocAsCode.DataContracts.Common/Constants.cs
+++ b/src/Microsoft.DocAsCode.DataContracts.Common/Constants.cs
@@ -12,7 +12,10 @@ public static class Constants
 
     public static class DocumentType
     {
+        public const string Conceptual = "Conceptual";
         public const string Toc = "Toc";
+        public const string ManagedReference = "ManagedReference";
+        public const string Resource = "Resource";
         public const string Redirection = "Redirection";
     }
 
diff --git a/src/Microsoft.DocAsCode.Plugins/DocumentType.cs b/src/Microsoft.DocAsCode.Plugins/DocumentType.cs
index 192289f8c88..79169dda1d4 100644
--- a/src/Microsoft.DocAsCode.Plugins/DocumentType.cs
+++ b/src/Microsoft.DocAsCode.Plugins/DocumentType.cs
@@ -10,5 +10,4 @@ public enum DocumentType
     Resource,
     Metadata,
     MarkdownFragments,
-    Redirection,
 }