1. Recent trends in energy-related CO2 emissions
2. Highway Diesel Progress Review, USEPA, Washington, June 2002, http://www.epa.gov/air/caaac/Dieselreview.pdf
3. Internet site of the Association of European Automobile Manufactures (ACEA), www.acea.be
4. Internet site of the Comity of French Automobile Manufactures (CCFA), www.ccfa.fr
5. Internet site of Deutsche Gegellschaft fur Technische Zusammenarbeit (GTZ), www.gtz.de/de/dokumente/en-International_Fuel_Prices_2005.pdf