1. Available at: http://en.wikipedia.org/wiki/1973_oil_crisis (accessed 12 February 2008).
2. J. Duffield, H. Shapouri, M. Graboski, R. McCormick and R. Wilson: ‘U.S. biodiesel development: new markets for conventional and genetically modified agricultural products’, USDA Agricultural Economic Report No. 770, USDA, Washington, DC, USA, 1998.
3. Data generated by McKinsey Consultants.
4. USDA: ‘World agricultural supply and demand estimates’, WASDE-455, USDA, Washington, DC, USA, 2008.