diff --git a/API/Schema/Chapter.cs b/API/Schema/Chapter.cs
index 695b826..ba8d36e 100644
--- a/API/Schema/Chapter.cs
+++ b/API/Schema/Chapter.cs
@@ -60,6 +60,9 @@ public class Chapter : IComparable<Chapter>
     {
         if (other is not { } otherChapter)
             throw new ArgumentException($"{other} can not be compared to {this}");
+        //Compare Ids for Collection-Comparisons
+        if(other.ChapterId.Equals(this.ChapterId))
+            return 0;
         return VolumeNumber?.CompareTo(otherChapter.VolumeNumber) switch
         {
             < 0 => -1,