Ancient Greek Skepticism An article on skepticism in Ancient Greece from the Internet Encyclopedia of Philosophy, by Harald Thorsrud of Temple University. http://www.iep.utm.edu/s/skepanci.htm
Ancient Scepticism and the Contra Academicos of St. Augustine A paper by Bernard Wills closely examines the logic of Augustine's response to ancient scepticism in his Contra Academicos. http://www.mun.ca/animus/1999vol4/wills4.htm
Ancient Skepticism From the Stanford Encyclopedia of Philosophy, by Leo Groarke. Article on the two movements in ancient philosophy, Pyrrhonism, and Academic Skepticism. http://plato.stanford.edu/entries/skepticism-ancient/
Aporetic Philosophia A discussion of the development of Greek skepticism from Pyrrho to Sextus Empiricus. A reference provided by Aporetic World Music. http://www.aporeticworld.com/historicalsources/