1. BMW Umweltbericht 1997/98 (1998), Munich, Germany (in German).
2. Daimler-Benz's Environmental Magazine 7/98 (1998), Internet Version (October 1998) available at Daimler-Benz website.
3. Industrial ecology: Adapting technology for a sustainable world;Frosch;Environment,1996
4. Towards a Green Automobile;Kuhndt,1997
5. National Round Table on the Environment and the Economy, 1997. Measuring eco-efficiency in business: developing a core set of eco-efficiency indicator, backgrounder. NRTEE, Ottawa.