P. J. O'Rourke (2007). “All the Trouble in the World: The Lighter Side of Overpopulation, Famine, Ecological Disaster, Ethnic Hatred, Plague, and Poverty”, p.201, Grove/Atlantic, Inc.
Foreign Relations of the United States 1969-1976, Volume E-5, Part 1, Documents on Sub-Saharan Africa 1969-1972, Document 258: Conversation Between President Nixon and the President's Assistant for National Security Affairs (Kissinger), Camp David, history.state.gov. September 24, 1972.