1. The Major Transitions in Evolution;Maynard Smith,1995
2. The miscellaneous transitions in evolution;McShea,2011
3. The Great Filter—Are We Almost Past It?http://www.hanson.gmu.edu/~greatfilter.html
4. Where are they? Why I hope the search for extreterrestrial life finds nothing;Bostrom;Technol. Rev.,2008
5. Evidence for life on Earth before 3,800 million years ago