diff --git a/dlibrary/dlibrary.py b/dlibrary/dlibrary.py
index 864d6b6..a862737 100755
--- a/dlibrary/dlibrary.py
+++ b/dlibrary/dlibrary.py
@@ -582,7 +582,7 @@ def unique_hierarchical_prefix_numbering(entries, start_point=0):
 def alphabetic_numbering(entries, start_point):
     alphabetized = {}
     for entry in entries:
-        ending = entry.stem[start_point:]
+        ending = nfc(entry.stem)[start_point:]
         if len(ending) > 1:
             return None
         index = 0 if ending == '' else ord(ending.lower()) - ord('a') + 1
@@ -591,8 +591,9 @@ def alphabetic_numbering(entries, start_point):
         alphabetized[(index,)] = [entry]
     indices = list(alphabetized.keys())
     indices.sort()
-    if indices != [(i,) for i in range(len(indices))]:
-        return None
+    for i in range(1, len(indices)):
+        if indices[i][0] - indices[i-1][0] != 1:
+            return None
     return alphabetized
 
 def check_extension(path, exts):