* Homer-Dixon, Thomas "The Upside of Down: Catastrophe, Creativity and the Renewal of Civilization", 2007 978-0-676-97723-3 Chapter 3 pp.
* Homer-Dixon، Thomas "The Upside of Down: Catastrophe, Creativity and the Renewal of Civilization", 2007 978-0-676-97723-3 Chapter 3 pp.