Rene Descartes (2013). “Discourse on the Method: Discourse On the Method of Rightly Conducting the Reason, and Seeking Truth In the Sciences (Beloved Books Edition)”, p.30, Lulu Press, Inc
George W. Bush's remarks on teaching American history and civic education at East Literature Magnet School in Nashville, Tennessee, georgewbush-whitehouse.archives.gov. September 17, 2002.