licensing exception for Autoconf, official text, version 3.0, 18 August 2009

project working toward the elimination of software patents

newsletter run by the FSF (Free Software Foundation)

free software license created by the Free Software Foundation

GNU version of the tar archiving utility

The Free Software Foundation's list of licenses & whether they are free, copyleft, GPL/GFDL compitable and/or have other practical problems

licencia de software libre para programas que corren en servidores

licencia orientada a proteger la libre distribución, modificación y uso de software

licencia de software libre

free software license created by the Free Software Foundation

historical free software license with copyleft

previous version of the GNU GPL (version 2), free software license with copyleft

latest version of the GNU GPL (version 3), free software license with copyleft

la Licencia Pública General Reducida de GNU versión 2.1

Licencia copyleft para contenido libre