References
Bettencourt L M A, Lobo J, Helbing D, Kuhnert C, West G B, 2007, "Growth, innovation, scaling, and the pace of life in cities" Proceedings of the National Academy of Sciences 104 7301 – 7306, doi:10.1073/pnas.0610172104
Brand S, 1999 The Clock of the Long Now: Time and Responsibility (Basic Books, New York)
Chandler T, 1987 Four Thousand Years of Urban Growth: An Historical Census (St David's University Press, Lampeter, Pembrokeshire)
Kali R, 2003, "The city as a giant component: a random graph approach to Zipf's law" Applied Economics Letters 10 717 – 720, doi:10.1080/1350485032000139006
Kremer M, 1993, "Population growth and technological change: one million B.C. to 1990" The Quarterly Journal of Economics 108 681 – 716, doi:10.2307/2118405
Kurzweil R, 2005 The Singularity is Near (Viking, New York)
Ravenstein E, 1885, "The laws of migration" Journal of the Statistical Society 46 167 – 235
Vinge V, 1993, "Technological singularity", a paper presented at the VISION-21 Symposium, NASA Lewis Research Center and the Ohio Aerospace Institute, 30 – 31 March, http://www-rohan.sdsu.edu/faculty/vinge/misc/WER2.html
von Foerster H, Mora P M, Amiot L W, 1960, "Doomsday: Friday, November 13, AD 2026" Science 132 1291 – 1295, doi:10.1126/science.132.3436.1291
9 references
4 
DOIs retrieved