All source files in the italk repository should give a copyright notice and license information.

The recommended language is:

/* 
 * Copyright (C) <year> ITALK Consortium, European Commission FP7 Grant Agreement no. 214668
 * Author <name of author> 
 * website: http://italkproject.org/
 * Permission is granted to copy, distribute, and/or modify this program
 * under the terms of the GNU General Public License, version 2 or any
 * later version published by the Free Software Foundation.
 *
 * A copy of the license can be found at
 * http://www.robotcub.org/cvsweb/cvsweb.cgi/italk/GPL.TXT
 *
 * 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
 */

If you have code for which you are not the copyright holder, but which is redistributable under terms that are compatible with the GPL, you may want to include it in the italk repository. It is not clear whether this is permitted. I describe here the procedure used in YARP (as opposed to italk) for such code. This does not imply the existence of a policy about such code for ITALK. The absolute minimum that would need to be present in each source file is:

A copyright statement with author name and year. Don't forget the year.
A license statement that is compatible with the GPL.

For YARP, the form of these statements was at a minimum:

/*
 * Copyright (C) 2007 Author McAuthor
 * CopyPolicy: Released under the terms of <the license name>
 */

The CopyPolicy line is useful to add for semi-automated license reviews of material in the repository.