COPYING.txt

CERTI 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.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program, in the file "gpl.txt"; if not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA

All the library components (e.g. libRTI, libCERTI, libHLA...)
components are licensed under the GNU Lesser General Public License.
This is a GPL-compatible license (this
is why CERTI can be considered as GPL software). You should have
received a copy of the GNU LGPL with this program, in the file
"lesser.txt".

In the "test" directory, the "Billard" application is GPL, and uses an
LGPL graphics library called "libgraphc".