GFDL

 —
 Copyright (c) Pablo Manuel Rizzo
 Permission is granted to copy, distribute and/or modify this
 document under the terms of the GNU Free Documentation License,
 Version 1.2 or any later version published by the Free Software
 Foundation; with no Invariant Sections, no Front-Cover Texts, and
 one Back-Cover Text: "El autor del texto original es Pablo Manuel Rizzo,
 puede ser contactado directamente al email info@pablorizzo.com"  A copy of 
 the license is included in the section entitled "GNU Free Documentation License".