"Janeane Garofalo To Keith Olbermann: ‘Herman Cain Hides The Racist Elements Of The Republican Party’" by James Crugnale, www.mediaite.com. September 29, 2011.
Justus von Liebig (1842). “Chemistry in its applications to agriculture and physiology: By Justus Liebig. Edited from the manuscript of the author by Lyon Playfair”, p.176