1. Almeida, P., Silva, P., 2005. Peak oil and the NYMEX futures market: Do investors believe in physical realities? In: Proceedings of the ASPO IV International Workshop on Oil and Gas Depletion, May, Lisbon.
2. ASPO, 2007. The growing gap. Association for the Study of Peak Oil and gas (ASPO), Newsletter 74. 〈http://www.peakoil.net/〉.
3. World oil production capacity model suggests output peak by 2006–07;Bakhtiari;Oil and Gas Journal,2004
4. Bakhtiari, A., 2006. The last frontier. Online article. 〈www.sfu.ca/~asamsamb/sb.htm〉.
5. An analysis of US and world oil production patterns using Hubbert-style curves;Bartlett;Mathematical Geology,2000