diff --git a/cycles_functional.ml b/cycles_functional.ml
index 54789b1..83d7016 100644
--- a/cycles_functional.ml
+++ b/cycles_functional.ml
@@ -1,3 +1,12 @@
+(**************************************************************************)
+(*  Copyright (C) 2012 Pietro Abate <pietro.abate@pps.jussieu.fr>         *)
+(*  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.                       *)
+(**************************************************************************)
 
 open Graph
 open ExtLib
diff --git a/cycles_iter.ml b/cycles_iter.ml
index c23a4fc..c8f4b12 100644
--- a/cycles_iter.ml
+++ b/cycles_iter.ml
@@ -1,3 +1,12 @@
+(**************************************************************************)
+(*  Copyright (C) 2012 Pietro Abate <pietro.abate@pps.jussieu.fr>         *)
+(*  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.                       *)
+(**************************************************************************)
 
 open Graph
 open ExtLib