1. World Energy Council, Global Energy Perspectives to 2050 and Beyond, International Institute for Applied Systems Analysis, Laxenberg, Austria, 1995.
2. US Department of Energy, International Energy Outlook 1996, Energy Information Agency, US DOE, DOE/EIA-0484(96), 1996.
3. Statistical Review of World Energy, British Petroleum plc, London, 1996.
4. World Resources Institute, World Resources 1996–97, Oxford University Press, Oxford, 1996.
5. J.E. Cohen, How Many People Can the Earth Support?, W. Norton, 1995.