diff --git a/Interfaces/IXBaseTagProvider.cs b/Interfaces/IXBaseTagProvider.cs
index e423dba..d60554a 100644
--- a/Interfaces/IXBaseTagProvider.cs
+++ b/Interfaces/IXBaseTagProvider.cs
@@ -26,13 +26,11 @@ namespace xTagService.Interfaces
         /// </summary>
         /// <param name="tag"></param>
         /// <param name="providedForId"></param>
-        /// <param name="forIndex"></param>
         /// <param name="connectionId"></param>
         /// <returns></returns>
         Task<bool> AddReference(
             string tag,
             TKey providedForId,
-            int forIndex = 0,
             string connectionId = null
         );
 
@@ -47,20 +45,18 @@ namespace xTagService.Interfaces
             string tag,
             XReference<TKey> reference,
             string connectionId = null
-        ); 
+        );
 
         /// <summary>
         /// Remove Reference a Tag for Specific Provided ID ...
         /// </summary>
         /// <param name="tag"></param>
         /// <param name="providedForId"></param>
-        /// <param name="forIndex">if null, removes all</param>
         /// <param name="connectionId"></param>
         /// <returns></returns>
         Task<bool> RemoveReference(
             string tag,
             TKey providedForId,
-            int? forIndex = null,
             string connectionId = null
         );
 
diff --git a/Providers/XBaseTagProvider.cs b/Providers/XBaseTagProvider.cs
index 4816057..741b413 100644
--- a/Providers/XBaseTagProvider.cs
+++ b/Providers/XBaseTagProvider.cs
@@ -40,14 +40,6 @@ namespace xTagService.Providers
         }
         #endregion
 
-        //
-        #region Identifier ...
-        public async Task<int> LastIndex(TKey providedForId)
-        {
-            return await Task.FromResult(GetLastIndex(providedForId));
-        }
-        #endregion
-
         //
         #region Referenced Actions ...
         /// <summary>
@@ -77,8 +69,8 @@ namespace xTagService.Providers
 
             //
             // Retrieve Last Index ...
-            var lastIndex = GetLastIndex(providedForId);
-            if (forIndex > lastIndex)
+            var referencesCount = await CountReferences(providedForId);
+            if (forIndex > referencesCount - 1)
             {
                 XException.NotFound.Throw();
             }
@@ -140,6 +132,32 @@ namespace xTagService.Providers
             return await Task.FromResult(result);
         }
 
+        /// <summary>
+        /// Count References ...
+        /// </summary>
+        /// <param name="providedForId"></param>
+        /// <returns></returns>
+        public async Task<int> CountReferences(TKey providedForId)
+        {
+            //
+            // Validate ...
+            var isValid = !providedForId.IsNull();
+            if (!isValid)
+            {
+                XException.InvalidArgs.Throw();
+            }
+
+            //
+            var identifier = GetProvidedID(providedForId);
+            var result = TagProvider.Repository
+                .AsQueryable()
+                .Where(t => t.References.Contains(identifier))
+                .Count();
+
+            //
+            return await Task.FromResult(result);
+        }
+
         /// <summary>
         /// Retrieve References of Specific Provided ID as Query ...
         /// </summary>
@@ -232,7 +250,6 @@ namespace xTagService.Providers
         public async Task<bool> AddReference(
             XTagDto model,
             TKey providedForId,
-            int forIndex = 0,
             string connectionId = null
         )
         {
@@ -263,34 +280,32 @@ namespace xTagService.Providers
             model = await TagProvider.Get(model.Id);
 
             //
-            var lastIndex = GetLastIndex(providedForId);
-            if (lastIndex == -1)
-            {
-                //
-                // This Means there isnot any Reference ...
-                forIndex = 0;
-                model.References.Add(new XReference<string>
-                {
-                    Index = forIndex,
-                    ProvidedFor = Provider,
-                    ReferencedTo = $"{providedForId}"
-                });
-            }
-            else
-            {
-                //
-                forIndex = lastIndex + 1;
+            // Retrieve all References ...
+            var references = await GetAllReferences(providedForId);
 
-                //
-                // Add New Reference ...
-                model.References.Add(new XReference<string>
-                {
-                    Index = forIndex,
-                    ProvidedFor = Provider,
-                    ReferencedTo = $"{providedForId}"
-                });
+            //
+            // Check isReferenced or not ...
+            result = references.Any(r => r.Id == model.Id &&
+                r.References.Any(rf => rf.ProvidedFor == Provider &&
+                    rf.ReferencedTo == $"{providedForId}"));
+            if (result)
+            {
+                return result;
             }
 
+            //
+            // Here means there is not any reference to ProvidedForId ...
+            int forIndex = await CountReferences(providedForId);
+
+            //
+            // Add Reference to Model ...
+            model.References.Add(new XReference<string>
+            {
+                Index = forIndex,
+                ProvidedFor = Provider,
+                ReferencedTo = $"{providedForId}"
+            });
+
             //
             // Update Data Base ...
             model = await TagProvider
@@ -321,15 +336,18 @@ namespace xTagService.Providers
             //
             // Validate ...
             // Since other Validations Handled in Calling, we Ignore them here ...
-            if (model.IsNull() ||
-                reference.IsNullOrDefault() ||
-                (!reference.ProvidedFor.IsNullOrEmpty() && reference.ProvidedFor != Provider))
+            var result =
+                !model.IsNull() &&
+                !reference.IsNullOrDefault() &&
+                reference.ProvidedFor == Provider &&
+                !reference.ReferencedTo.IsNull();
+            if (!result)
             {
                 XException.InvalidArgs.Throw();
             }
 
             //
-            var result = await AddReference(
+            result = await AddReference(
                 model: model,
                 connectionId: connectionId,
                 providedForId: reference.ReferencedTo
@@ -350,15 +368,16 @@ namespace xTagService.Providers
         public async Task<bool> RemoveReference(
             XTagDto model,
             TKey providedForId,
-            int? forIndex = null,
             string connectionId = null
         )
         {
             //
             // Validate ...
-            if (model.IsNull() ||
-                providedForId.IsNull() ||
-                !model.Id.IsValidIntId())
+            var result =
+            !providedForId.IsNull() &&
+            !model.IsNullOrDefault() &&
+            model.Id.IsValidIntId();
+            if (!result)
             {
                 XException.InvalidArgs.Throw();
             }
@@ -366,37 +385,95 @@ namespace xTagService.Providers
             //
             // Retrieve Model ...
             model = await TagProvider.Get(model.Id);
-            if (model.IsNullOrDefault())
+            result = !model.IsNullOrDefault();
+            if (!result)
             {
                 XException.NotFound.Throw();
             }
 
             //
             // Check Model Reference to ID ...
-            var isReferenced = model.References
-                .Any(r => r.ProvidedFor == Provider &&
-                r.ReferencedTo == $"{providedForId}" &&
-                (!forIndex.HasValue || r.Index == forIndex.Value));
-
-            //
-            var result = false;
-            if (isReferenced)
+            var referencesCount = await CountReferences(providedForId);
+            result = referencesCount == 0;
+            if (result)
             {
                 //
-                model.References = model.References
-                    .Where(r => r.ProvidedFor != Provider ||
-                        (r.ProvidedFor == Provider &&
-                        r.ReferencedTo != $"{providedForId}" &&
-                        (!forIndex.HasValue || r.Index == forIndex.Value)))
-                    .ToList();
+                // There is not any Reference to Remove ...
+                return result;
+            }
 
+            //
+            // Check Model is Trully Referenced to ProvidedForId or not ...
+            var reference = model.References
+                .FirstOrDefault(r => r.ProvidedFor == Provider &&
+                r.ReferencedTo == $"{providedForId}");
+            result = !model.IsNullOrDefault();
+            if (!result)
+            {
+                XException.ActionFailed.Throw();
+            }
+
+            //
+            // Remove Referenced Item from Model ...
+            model.References = model.References
+                .Where(r => !(r.ProvidedFor == Provider &&
+                r.ReferencedTo == $"{providedForId}"))
+                .ToList();
+
+            //
+            // Update DataBase ...
+            model = await TagProvider.Update(
+                id: model.Id,
+                model: model,
+                connectionId: connectionId
+            );
+
+            //
+            result = !model.IsNullOrDefault();
+            if (!result)
+            {
+                XException.ActionFailed.Throw();
+            }
+
+            //
+            // Here We Have to Re Arrange Indexed ...
+            if (reference.Index < referencesCount - 1)
+            {
                 //
-                model = await TagProvider.Update(
-                    id: model.Id,
-                    model: model,
-                    connectionId: connectionId
-                );
-                result = !model.IsNullOrDefault();
+                var startIndex = reference.Index + 1;
+                for (int i = startIndex; i < referencesCount; i++)
+                {
+                    //
+                    var dto = await GetReference(
+                        forIndex: i,
+                        providedForId: providedForId
+                    );
+                    if (!dto.IsNullOrDefault())
+                    {
+                        //
+                        dto.References
+                        .ToList()
+                        .ForEach(iref =>
+                        {
+                            //
+                            if (
+                                iref.Index == i &&
+                                iref.ProvidedFor == Provider &&
+                                iref.ReferencedTo == reference.ReferencedTo
+                            )
+                            {
+                                iref.Index = i - 1;
+                            }
+                        });
+
+                        //
+                        dto = await TagProvider.Update(
+                            id: dto.Id,
+                            model: dto,
+                            connectionId: connectionId
+                        );
+                    }
+                }
             }
 
             //
@@ -428,7 +505,6 @@ namespace xTagService.Providers
             //
             var result = await RemoveReference(
                 model: model,
-                forIndex: reference.Index,
                 connectionId: connectionId,
                 providedForId: reference.ReferencedTo
             );
@@ -501,7 +577,6 @@ namespace xTagService.Providers
         public async Task<bool> AddReference(
             string tag,
             TKey providedForId,
-            int forIndex = 0,
             string connectionId = null
         )
         {
@@ -549,7 +624,6 @@ namespace xTagService.Providers
             //
             result = await AddReference(
                 model: dto,
-                forIndex: forIndex,
                 connectionId: connectionId,
                 providedForId: providedForId
             );
@@ -576,33 +650,21 @@ namespace xTagService.Providers
 
             //
             // Validate ...
-            result = !tag.IsNullOrEmpty();
+            result =
+                !tag.IsNullOrEmpty() &&
+                !reference.IsNullOrDefault() &&
+                reference.ProvidedFor == Provider &&
+                !reference.ReferencedTo.IsNull();
             if (!result)
             {
                 XException.InvalidArgs.Throw();
             }
 
-            //
-            // Check Tag Exists ...
-            result = IsExists(tag);
-            if (!result)
-            {
-                XException.NotFound.Throw();
-            }
-
-            //
-            var dto = GetTagByTag(tag);
-            result = !dto.IsNullOrDefault();
-            if (!result)
-            {
-                XException.ActionFailed.Throw();
-            }
-
             //
             result = await AddReference(
-                model: dto,
-                reference: reference,
-                connectionId: connectionId
+                tag: tag,
+                connectionId: connectionId,
+                providedForId: reference.ReferencedTo
             );
 
             //
@@ -620,7 +682,6 @@ namespace xTagService.Providers
         public async Task<bool> RemoveReference(
             string tag,
             TKey providedForId,
-            int? forIndex = null,
             string connectionId = null
         )
         {
@@ -629,7 +690,9 @@ namespace xTagService.Providers
 
             //
             // Validate ...
-            result = !tag.IsNullOrEmpty();
+            result =
+                !tag.IsNullOrEmpty() &&
+                !providedForId.IsNull();
             if (!result)
             {
                 XException.InvalidArgs.Throw();
@@ -680,33 +743,21 @@ namespace xTagService.Providers
 
             //
             // Validate ...
-            result = !tag.IsNullOrEmpty();
+            result =
+                !tag.IsNullOrEmpty() &&
+                !reference.IsNullOrDefault() &&
+                !reference.ReferencedTo.IsNull() &&
+                reference.ProvidedFor == Provider;
             if (!result)
             {
                 XException.InvalidArgs.Throw();
             }
 
-            //
-            // Check Tag Exists ...
-            result = IsExists(tag);
-            if (!result)
-            {
-                XException.NotFound.Throw();
-            }
-
-            //
-            var dto = GetTagByTag(tag);
-            result = !dto.IsNullOrDefault();
-            if (!result)
-            {
-                XException.ActionFailed.Throw();
-            }
-
             //
             result = await RemoveReference(
-                model: dto,
-                reference: reference,
-                connectionId: connectionId
+                tag: tag,
+                connectionId: connectionId,
+                providedForId: reference.ReferencedTo
             );
 
             //
@@ -740,55 +791,7 @@ namespace xTagService.Providers
         )
         {
             //
-            var result = $"{GetProvidedID(providedForId, splitter)}{splitter}{providedForId}";
-
-            //
-            return result;
-        }
-
-        private int GetLastIndex(TKey providedForId)
-        {
-            //
-            var result = -1;
-
-            //
-            // Validate ...
-            var isValid = !providedForId.IsNull();
-            if (!isValid)
-            {
-                XException.InvalidArgs.Throw();
-            }
-
-            //
-            var identifier = GetProvidedID(providedForId);
-
-            //
-            var all = TagProvider.Repository
-                .AsQueryable()
-                .Where(t => t.References
-                    .Contains(identifier))
-                .Select(t => t.References)
-                .AsEnumerable();
-            if (all.IsNull() || !all.HasChild())
-            {
-                result = -1;
-            }
-            else
-            {
-                //
-                var references = all
-                    .SelectMany(a => a.ParseXReferenceList<TKey>())
-                    .OrderByDescending(r => r.Index)
-                    .ToList();
-                if (!references.IsNull() && references.HasChild())
-                {
-                    result = references[0].Index;
-                }
-                else
-                {
-                    result = -1;
-                }
-            }
+            var result = $"{GetProvidedID(providedForId, splitter)}{splitter}{forIndex}";
 
             //
             return result;