1. J. Diamond, Collapse: how societies choose to fail or succeed, Penguin Group (USA) Inc., 2005.
2. Hawking Proposes Space Colonies to Mitigate Global Threats, (Report of speech by Stephen Hawkins in Hong Kong, June 19, 2006. Science in the News Weekly, Sigma Xi/American Scientist, vol.4, No.25. June 20, 2006. See also: Frank O’Connell, An Invisible, Deadly Barrier to Journeys Through Space, New York Times, February 28, 2006.
3. A Study of History, Abridgement of Volumes I–VI and Volumes VII–X;Toynbee,1957
4. Judgment Under Uncertainty: Heuristics and Biases;Kahneman,1982
5. The Atlantic heat conveyor slows;Quadfasel;Nature,2005