Documentation files should have license notices also.  Manuals should
use the GNU Free Documentation License.  Following is an example of the
license notice to use after the copyright line(s) using all the
features of the GFDL.

@smallexample
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``GNU General Public License'', with the
Front-Cover Texts being ``A GNU Manual'', and with the Back-Cover Texts
as in (a) below.  A copy of the license is included in the section
entitled ``GNU Free Documentation License''.