diff --git a/cycles.py b/cycles.py
index aaa6747..4a3c71a 100644
--- a/cycles.py
+++ b/cycles.py
@@ -52,6 +52,13 @@ procedure circuit_enumeration;
   end;
 """
 
+# Copyright (C) 2012 Johannes Schauer <j.schauer@email.de>
+#
+# This library is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+
 import sys
 
 if len(sys.argv) < 3: