diff --git a/Interfaces/IXBaseReferenced.cs b/Interfaces/IXBaseReferenced.cs
new file mode 100644
index 0000000..0129904
--- /dev/null
+++ b/Interfaces/IXBaseReferenced.cs
@@ -0,0 +1,81 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using xIdentityModels.Models;
+
+namespace xIdentityService.Interfaces
+{
+    /// <summary>
+    /// a Referenced Service is a Service which can Referenced to other Items ...
+    /// </summary>
+    public interface IXBaseReferenced
+    {
+        /// <summary>
+        /// Get Reference Identifier for Specified Provider and Specified Item ...
+        /// </summary>
+        /// <param name="providedFor"></param>
+        /// <param name="forProvidedId"></param>
+        /// <returns></returns>
+        string GetIdentifier<TKey>(
+            string providedFor,
+            TKey forProvidedId
+        );
+
+        /// <summary>
+        /// Check Specified Item has Refernce to Provider ...
+        /// </summary>
+        /// <param name="providedFor"></param>
+        /// <param name="forProvidedId"></param>
+        /// <param name="id"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        Task<bool> IsProvidedFor<TKey>(
+            string providedFor,
+            TKey forProvidedId,
+            Guid id,
+            CancellationToken cancellationToken = default
+        );
+
+        /// <summary>
+        /// Add Specified Reference to Specified Item ...
+        /// </summary>
+        /// <param name="providedFor"></param>
+        /// <param name="forProvidedId"></param>
+        /// <param name="id"></param>
+        /// <param name="forIndex"></param>
+        /// <param name="userInfo"></param>
+        /// <param name="connectionId"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        Task AddReference<TKey>(
+            string providedFor,
+            TKey forProvidedId,
+            Guid id,
+            int forIndex = 0,
+            XUserClaimsInfoDto userInfo = null,
+            string connectionId = null,
+            CancellationToken cancellationToken = default
+        );
+
+        /// <summary>
+        /// Remove Specified Reference from Specified Item ...
+        /// </summary>
+        /// <param name="providedFor"></param>
+        /// <param name="forProvidedId"></param>
+        /// <param name="id"></param>
+        /// <param name="forIndex"></param>
+        /// <param name="userInfo"></param>
+        /// <param name="connectionId"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        Task RemoveReference<TKey>(
+            string providedFor,
+            TKey forProvidedId,
+            Guid id,
+            int forIndex = 0,
+            XUserClaimsInfoDto userInfo = null,
+            string connectionId = null,
+            CancellationToken cancellationToken = default
+        );                
+    }
+}
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