Ben R. Finney (ed.). Interstellar Migration, the Biological Revolution, and the Future of the Galaxy. University of California Press. p. 278. ISBN978-0-520-05898-9. Consultado el 12 de junio de 2016. «...interstellar wars will be extremely rare, much rarer than warfare has been on Earth. This will be a consequence of the enormous distances between the stars and large travel times between civilizations... a typical civilization might be involved in a major war only once in 50,000 years, perhaps much longer.»
