Euler was downloaded from http://euler.sourceforge.net/

Upstream Authors: Dr. René Grothmann <grothm@ku-eichstaett.de>
                  Eric Boucharé <bouchare.eric@wanadoo.fr>
                  Puji Prasetiyo <aripujiprasetiyo@yahoo.com>

Copyright © 1988-2005 Dr. René Grothmann
          © 2001-2005 Eric Boucharé
          © 2005 Puji Prasetiyo

License:

   Euler is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

On Debian systems, the complete text of the GNU General
Public License can be found in `/usr/share/common-licenses/GPL'.