Chalk, Andy. «John Carmack Argues Against Native Linux Games». The Escapist, 06-02-2013. Arxivat de l'original el 13 de gener 2014. [Consulta: 29 setembre 2013]. «He reiterated his support for improving emulation as the "proper technical direction for gaming on Linux," noting that native ports don't do much that a good emulator wouldn't be able to handle.»
esrb.org
Entertainment Software Rating Board. «Game ratings». Arxivat de l'original el 16 de febrer 2006. [Consulta: 4 desembre 2004].
Chalk, Andy. «John Carmack Argues Against Native Linux Games». The Escapist, 06-02-2013. Arxivat de l'original el 13 de gener 2014. [Consulta: 29 setembre 2013]. «He reiterated his support for improving emulation as the "proper technical direction for gaming on Linux," noting that native ports don't do much that a good emulator wouldn't be able to handle.»