http://discuss.fogcreek.com/joelonsoftware/default.asp?cmd=show&ixPost=2748
http://stuff.techwhack.com/archives/2004/12/25/firefox-vs-opera/
http://chooseopera.com/FAQs/WhyOpera.html
http://tntluoma.com/beyond30/2003/08/opera_vs_mozilla
http://www.webmasterworld.com/forum21/9384-3-10.htm
http://discuss.fogcreek.com/joelonsoftware/default.asp?cmd=show&ixPost=2748