Sophism

Catholic Encyclopedia: Sophists
Article by William Turner.
http://www.newadvent.org/cathen/14145c.htm

Internet Encyclopedia of Philosophy: Sophists
Concise article on the historical context of this movement.
http://www.iep.utm.edu/s/sophists.htm

Sophism and the Socratic/Platonic Project
Notes on the relations between Sophism and Platonism.
http://www.drury.edu/ess/History/Ancient/Plato1.html

Wikipedia: Sophist
Short article on the historical meaning of this term.
http://en.wikipedia.org/wiki/Sophist/