diff --git a/SabreTools.DatFiles.Test/ItemDictionaryDBTests.cs b/SabreTools.DatFiles.Test/ItemDictionaryDBTests.cs
index 67809a01..ebea97cf 100644
--- a/SabreTools.DatFiles.Test/ItemDictionaryDBTests.cs
+++ b/SabreTools.DatFiles.Test/ItemDictionaryDBTests.cs
@@ -112,7 +112,22 @@ namespace SabreTools.DatFiles.Test
 
         #region GetMachineForItem
 
-        // TODO: Add GetMachineForItem tests
+        [Fact]
+        public void GetMachineForItemTest()
+        {
+            Source source = new Source(0, source: null);
+            Machine machine = new Machine();
+            DatItem item = new Rom();
+
+            var dict = new ItemDictionaryDB();
+            long machineIndex = dict.AddMachine(machine);
+            long sourceIndex = dict.AddSource(source);
+            long itemIndex = dict.AddItem(item, machineIndex, sourceIndex);
+
+            var actual = dict.GetMachineForItem(itemIndex);
+            Assert.Equal(0, actual.Key);
+            Assert.NotNull(actual.Value);
+        }
 
         #endregion
 
@@ -134,7 +149,22 @@ namespace SabreTools.DatFiles.Test
 
         #region GetSourceForItem
 
-        // TODO: Add GetSourceForItem tests
+        [Fact]
+        public void GetSourceForItemTest()
+        {
+            Source source = new Source(0, source: null);
+            Machine machine = new Machine();
+            DatItem item = new Rom();
+
+            var dict = new ItemDictionaryDB();
+            long machineIndex = dict.AddMachine(machine);
+            long sourceIndex = dict.AddSource(source);
+            long itemIndex = dict.AddItem(item, machineIndex, sourceIndex);
+
+            var actual = dict.GetSourceForItem(itemIndex);
+            Assert.Equal(0, actual.Key);
+            Assert.NotNull(actual.Value);
+        }
 
         #endregion
 
diff --git a/SabreTools.DatFiles/ItemDictionaryDB.cs b/SabreTools.DatFiles/ItemDictionaryDB.cs
index 144a9869..c0ed79aa 100644
--- a/SabreTools.DatFiles/ItemDictionaryDB.cs
+++ b/SabreTools.DatFiles/ItemDictionaryDB.cs
@@ -421,7 +421,6 @@ namespace SabreTools.DatFiles
 
             var machine = _machines[machineIndex];
             return new KeyValuePair<long, Machine?>(machineIndex, machine);
-
 #endif
         }
 
@@ -446,6 +445,15 @@ namespace SabreTools.DatFiles
         /// </summary>
         public KeyValuePair<long, Source?> GetSourceForItem(long itemIndex)
         {
+#if NET40_OR_GREATER || NETCOREAPP
+            if (!_itemToSourceMapping.TryGetValue(itemIndex, out long sourceIndex))
+                return new KeyValuePair<long, Source?>(-1, null);
+
+            if (!_sources.TryGetValue(sourceIndex, out var source))
+                return new KeyValuePair<long, Source?>(-1, null);
+
+            return new KeyValuePair<long, Source?>(sourceIndex, source);
+#else
             if (!_itemToSourceMapping.ContainsKey(itemIndex))
                 return new KeyValuePair<long, Source?>(-1, null);
 
@@ -453,7 +461,9 @@ namespace SabreTools.DatFiles
             if (!_sources.ContainsKey(sourceIndex))
                 return new KeyValuePair<long, Source?>(-1, null);
 
-            return new KeyValuePair<long, Source?>(sourceIndex, _sources[sourceIndex]);
+            var source = _sources[sourceIndex];
+            return new KeyValuePair<long, Source?>(sourceIndex, source);
+#endif
         }
 
         /// <summary>
@@ -612,7 +622,7 @@ namespace SabreTools.DatFiles
             PerformItemBucketing(index, _bucketedBy, lower: true, norename: true);
 
             // Return the used index
-            return index - 1;
+            return index;
         }
 
         #endregion