1. Probability 1: Why There Must Be Intelligent Life in the Universe;Aczel,1998
2. Placing a limit on star-fed Kardashev type III civilisations;Annis;J. Br. Interplanet. Soc.,1999
3. Transit light-curve signatures of artificial objects;Arnold;Astrophys. J.,2005
4. The Anthropic Cosmological Principle;Barrow,1986
5. Intelligent Life in the Universe;Basalla,2006