1. Lee, R. 1969. !Kung Bushmen subsistence: An input-output analysis. In Environment and cultural behavior, ed. A.P. Vayda, 47–79. New York: Natural History Press.
2. Shostak, Marjorie. 2000. Nisa: The life and words of a !Kung Woman. Cambridge, MA: Harvard University Press. Glaub, M. and C.A.S. Hall. 2017. Evolutionary implications of persistence hunting: An examination of energy return on investment for !Kung Hunting. Human Ecology 45:393–401.
3. Martin, P.S. 1973. The Discovery of America. Science 179: 969–974.
4. This analysis is based mostly on a series of papers in Science magazine of 2 March 2001.
5. Culotta, E., A. Sugden, and B. Hanson. 2001. Humans on the move. Science 291: 1721–1753.