Bruce Byfield: 7 Reasons Why Free Software Is Losing Influence: Page 2.Datamation.com, 22. November 2011, abgerufen am 23. August 2013: „At the time, the decision seemed sensible in the face of a deadlock. But now, GPLv2 is used for 42.5% of free software, and GPLv3 for less than 6.5%, according to Black Duck Software.“
Frequently Asked Questions about the GNU Licenses – Is GPLv3 compatible with GPLv2? gnu.org, abgerufen am 13. April 2011 (englisch): „No. Some of the requirements in GPLv3, such as the requirement to provide Installation Information, do not exist in GPLv2. As a result, the licenses are not compatible: if you tried to combine code released under both these licenses, you would violate section 6 of GPLv2.“
David Chisnall: The Failure of the GPL.informit.com, 31. August 2009, abgerufen am 24. Januar 2016: „The GPL places additional restrictions on the code, and therefore is incompatible. You can combine APSL, MPL, CDDL, Apache, and BSD-licensed code in the same project easily, but you can only combine one of these with GPLv2 code. Even the Free Software Foundation can't manage to get it right. Version 3 of the LGPL, for example, is incompatible with version 2 of the GPL. This has caused a problem recently for a few GNU library projects that wanted to move to LGPLv3 but were used by other projects that were GPLv2-only.“
Linus Torvalds: COPYING. kernel.org, abgerufen am 13. August 2013: „Also note that the only valid version of the GPL as far as the kernel is concerned is _this_ particular version of the license (ie v2, not v2.2 or v3.x or whatever), unless explicitly otherwise stated.“
landley.net
Rob Landley: CELF 2013 Toybox talk - http://landley.net/talks/celf-2013.txt. landley.net, abgerufen am 21. August 2013 (englisch): „GPLv3 broke "the" GPL into incompatible forks that can't share code. […] FSF expected universal compliance, but hijacked lifeboat clause when boat wasn't sinking. […]“
libregraphicsworld.org
Alexandre Prokoudine: What's up with DWG adoption in free software? libregraphicsworld.org, 26. Januar 2012, abgerufen am 5. Dezember 2015: „[Blender's Toni Roosendaal:] "Blender is also still "GPLv2 or later". For the time being we stick to that, moving to GPL 3 has no evident benefits I know of."“
lwn.net
Lizenzbedingungen; Linux-Gerätetreiber, 2. Auflage. (Englisch: 1, 2); Hinweis: die englische "3rd edition" besagt etwas vorsichtiger, dass das Nutzen von binären ("binary form only" — also ohne Quellcode) "ladbaren Kernel-Gerätetreiber-Modulen unter Linux", nicht eindeutig ist (bislang aber jedenfalls geduldet): Link
Corbet: Busy busy busybox. lwn.net, 1. Oktober 2006, abgerufen am 21. November 2015: „Since BusyBox can be found in so many embedded systems, it finds itself at the core of the GPLv3 anti-DRM debate. […] The real outcomes, however, are this: BusyBox will be GPLv2 only starting with the next release. It is generally accepted that stripping out the "or any later version" is legally defensible, and that the merging of other GPLv2-only code will force that issue in any case“
Rob Landley: Re: Move GPLv2 vs v3 fun… lwn.net, 9. September 2006, abgerufen am 21. November 2015: „Don't invent a straw man argument please. I consider licensing BusyBox under GPLv3 to be useless, unnecessary, overcomplicated, and confusing, and in addition to that it has actual downsides. 1) Useless: We're never dropping GPLv2.“
New Media Rights: Open Source Licensing Guide.California Western School of Law, 12. September 2008, abgerufen am 28. November 2015: „The GPL license is ‘viral,’ meaning any derivative work you create containing even the smallest portion of the previously GPL licensed software must also be licensed under the GPL license.“
Lizenzbedingungen; Linux-Gerätetreiber, 2. Auflage. (Englisch: 1, 2); Hinweis: die englische "3rd edition" besagt etwas vorsichtiger, dass das Nutzen von binären ("binary form only" — also ohne Quellcode) "ladbaren Kernel-Gerätetreiber-Modulen unter Linux", nicht eindeutig ist (bislang aber jedenfalls geduldet): Link
oreilly.de
Lizenzbedingungen; Linux-Gerätetreiber, 2. Auflage. (Englisch: 1, 2); Hinweis: die englische "3rd edition" besagt etwas vorsichtiger, dass das Nutzen von binären ("binary form only" — also ohne Quellcode) "ladbaren Kernel-Gerätetreiber-Modulen unter Linux", nicht eindeutig ist (bislang aber jedenfalls geduldet): Link
phoronix.com
Michael Larabel: FSF Wastes Away Another "High Priority" Project.Phoronix, 24. Januar 2013, abgerufen am 22. August 2013 (englisch): „Both LibreCAD and FreeCAD both want to use LibreDWG and have patches available for supporting the DWG file format library, but can't integrate them. The programs have dependencies on the popular GPLv2 license while the Free Software Foundation will only let LibreDWG be licensed for GPLv3 use, not GPLv2.“
redirecter.toolforge.org
Mark: The Curse of Open Source License Proliferation. socializedsoftware.com, 8. Mai 2008, archiviert vom Original am 8. Dezember 2015; abgerufen am 30. November 2015: „Currently the decision to move from GPL v2 to GPL v3 is being hotly debated by many open source projects.“
Top 20 licenses.Black Duck Software, 23. August 2013, archiviert vom Original am 19. Juli 2016; abgerufen am 23. August 2013: „1. GNU General Public License (GPL) 2.0 33 %, 2. Apache License 13 %, 3. GNU General Public License (GPL) 3.0 12%“
Matthew Aslett: The trend towards permissive licensing. the451group.com, 6. Juni 2011, archiviert vom Original (nicht mehr online verfügbar) am 11. Mai 2013; abgerufen am 23. August 2013: „[…] the GPL family of licenses has fallen to 61 % today from 70 % […] In comparison the number of Apache licensed projects grew 46 % over the past two years, while the number of MIT licensed projects grew 152 %.“
Open Source License Data. In: Open Source Resource Center. Black Duck Software, archiviert vom Original (nicht mehr online verfügbar) am 13. Januar 2013; abgerufen am 6. Dezember 2012 (englisch).
Rémi Denis-Courmont: VLC media player to remain under GNU GPL version 2. videolan.org, abgerufen am 21. November 2015: „In 2001, VLC was released under the OSI-approved GNU General Public version 2, with the commonly-offered option to use "any later version" thereof (though there was not any such later version at the time). Following the release by the Free Software Foundation (FSF) of the new version 3 of its GNU General Public License (GPL) on the 29th of June 2007, contributors to the VLC media player, and other software projects hosted at videolan.org, debated the possibility of updating the licensing terms for future version of the VLC media player and other hosted projects, to version 3 of the GPL. […] There is strong concern that these new additional requirements might not match the industrial and economic reality of our time, especially in the market of consumer electronics. It is our belief that changing our licensing terms to GPL version 3 would currently not be in the best interest of our community as a whole. Consequently, we plan to keep distributing future versions of VLC media player under the terms of the GPL version 2.“
Mark: The Curse of Open Source License Proliferation. socializedsoftware.com, 8. Mai 2008, archiviert vom Original am 8. Dezember 2015; abgerufen am 30. November 2015: „Currently the decision to move from GPL v2 to GPL v3 is being hotly debated by many open source projects.“
Top 20 licenses.Black Duck Software, 23. August 2013, archiviert vom Original am 19. Juli 2016; abgerufen am 23. August 2013: „1. GNU General Public License (GPL) 2.0 33 %, 2. Apache License 13 %, 3. GNU General Public License (GPL) 3.0 12%“
Matthew Aslett: The trend towards permissive licensing. the451group.com, 6. Juni 2011, archiviert vom Original (nicht mehr online verfügbar) am 11. Mai 2013; abgerufen am 23. August 2013: „[…] the GPL family of licenses has fallen to 61 % today from 70 % […] In comparison the number of Apache licensed projects grew 46 % over the past two years, while the number of MIT licensed projects grew 152 %.“
Open Source License Data. In: Open Source Resource Center. Black Duck Software, archiviert vom Original (nicht mehr online verfügbar) am 13. Januar 2013; abgerufen am 6. Dezember 2012 (englisch).
Lizenzbedingungen; Linux-Gerätetreiber, 2. Auflage. (Englisch: 1, 2); Hinweis: die englische "3rd edition" besagt etwas vorsichtiger, dass das Nutzen von binären ("binary form only" — also ohne Quellcode) "ladbaren Kernel-Gerätetreiber-Modulen unter Linux", nicht eindeutig ist (bislang aber jedenfalls geduldet): Link