Hippias of Elis  
   Concise scholarly biography of this discoverer of the quadratrix, from the MacTutor History of Mathematics.
   http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Hippias.html

Hippias  
   Wikipedia entry on this ancient polymath, including some material from the 1911 Britannica.
   http://www.wikipedia.org/wiki/Hippias

Hippias Biography  
   Constructed from excerpts from various of Plato's dialogues which mention this Sophist.
   http://www.cnu.edu/academics/phil/carr/HippiBio.htm

Hippias's Quadratrix  
   Some brief notes on Hippias' attempt to square the circle using this curve, "a pictorial representation of the irrationality of pi."
   http://www.perseus.tufts.edu/GreekScience/Students/Tim/Quadratrix.html