APA Style Citation
Protagoras. (n.d.). BrainyQuote.com. Retrieved May 19, 2013, from BrainyQuote.com Web site: http://www.brainyquote.com/quotes/authors/p/protagoras.html
Chicago Style Citation
Protagoras. BrainyQuote.com, Xplore Inc, 2013. http://www.brainyquote.com/quotes/authors/p/protagoras.html, accessed May 19, 2013.
MLA Style Citation
"Protagoras." BrainyQuote.com. Xplore Inc, 2013. 19 May 2013. http://www.brainyquote.com/quotes/authors/p/protagoras.html
