In 2002 and 2003 the controversy about using reasonable and non-discriminatory (RAND) licensing for the use of patented technology in web standards increased. Bruce Perens, important associations as FSF or FFII and others have argued that the use of patents restricts who can implement a standard to those able or willing to pay for the use of the patented technology. The requirement to pay some small amount per user, is often an insurmountable problem for free/open source software implementations which can be redistributed by anyone. Royalty free (RF) licensing is generally the only possible license for free/open source software implementations. Version 3 of the GNU General Public License includes a section that enjoins anyone who distributes a program released under the GPL from enforcing patents on subsequent users of the software or derivative works.