(n.d.). Gestalt theory: Isomorphism. BAmagazine. Retrieved June 19, 2012 from http://www.bamagazine.com/PDF-0700-Gestalt-theory-Isomorphism-p/d1510700.htm

Knight, L. (2008, March). The rules of gestalt theory and how to apply it to your graphic design layouts. Retrieved June 19, 2012 from
http://www.allgraphicdesign.com/graphicsblog/2008/03/04/the-rules-of-the-gestalt-theory-and-how-to-apply-it-to-your-graphic-design-layouts/