requiring all modified and extended versions of the program to be free as well." <ref>http://www.gnu.org/copyleft/</ref>
requiring all modified and extended versions of the program to be free as well." <ref>http://www.gnu.org/copyleft/</ref>
−
"'''Share-alike'''" works, unlike "copylefted" works, don't have to be free. For example, [[CC-BY-NC-SA]] is a share alike work which is not free. <ref>[http://robmyers.org/weblog/2008/02/noncommercial-sharealike-is-not-copyleft.html NonCommercial Sharealike Is Not Copyleft]</ref>
+
"'''Share-alike'''" works, unlike "copylefted" works, don't have to be free. For example, [[CC-BY-NC-SA]] is a share alike work which is not free. <ref>[http://robmyers.org/weblog/2008/02/noncommercial-sharealike-is-not-copyleft.html NonCommercial Sharealike Is Not Copyleft] by [[Rob Myers]]</ref>