Reference added

smichr · Nov 27, 2022 · 3522ca5 · 3522ca5
1 parent 1b234a8
commit 3522ca5
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/sympy/utilities/iterables.py b/sympy/utilities/iterables.py
@@ -2545,6 +2545,10 @@ def necklaces(n, k, free=False):
 
     .. [1] http://mathworld.wolfram.com/Necklace.html
 
+    .. [2] Frank Ruskey, Carla Savage, and Terry Min Yih Wang,
+        Generating necklaces, Journal of Algorithms 13 (1992), 414–430;
+        https://doi.org/10.1016/0196-6774(92)90047-G
+
     """
     # The FKM algorithm
     if k == 0 and n > 0: