• European Commission. (2003) European Biofuels Directive 2003/30/EC. Commission of the European Communities, Brussels.
  • European Commission. (2007) Communication from the Commission to the Council and the European Parliament – Biofuels Progress Report: Report on the Progress Made in the Use of Biofuels and Other Renewable Fuels in the Member States of the European Union. Commission of the European Communities, Brussels.
  • Goldemberg, J., Coelho, S.T., Nastri, P.M. & Lucon, O. (2004) Ethanol learning curve – the Brazilian experience. Biomass Bioenergy 26, 301304.
  • Hunter, C. & Shaw, J. (2005) Applying the ecological footprint to ecotourism scenarios. Environ. Conserv. 32, 294304.
  • Iles, A. (2005) Learning in sustainable agriculture: food miles and missing objects. Environ. Values 14, 163183.
  • IPCC. (2007) Climate Change 2007: The Physical Science Basis. Summary for Policy Makers. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Intergovernmental Panel on Climate Change, Paris.
  • Ragauskas, A.J., Williams, C.K., Davison, B.H., Britovse, G., Cairney, J., Eckert, C.A., Frederick, W.J., Jr, Hallett, J.P., Leak, D.J., Liotta, C.L., Mielenz, J.R., Murphy, R., Templer, R., Tschaplinski, T. (2006) The path forward for biofuels and biomaterials. Science 311, 484489.
  • Wardle, D.A. (2003) Global sale of green air travel supported using biodiesel. Renew. Sust. Energ. Rev. 7, 164.