I need to download FireFox 13.0 to run a internet program. Where can I download FireFox 13.0?

See this article about how to install multiple versions on Mac OS X: * http://www.businessinsider.com/how-to-run-firefox-4-and-3-simultaneously-in-mac-os-x-with-multiple-firefox-profiles-2011-3 Only use the older Firefox version when you really need it. *ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/13.0.1/mac/