1. Ljungström S. Personal communication. Gothenburg (Sweden): Competence Center for Catalysis, Chalmers University of Technology. September 1998–March 1999.
2. Handbook of heterogeneous catalysis, vol. 4;Ertl,1997
3. Jobson E. Personal communication. Gothenburg (Sweden): AB Volvo Technological Development, November 1998 and February 1999.
4. LCA database version 2.0, Gothenburg (Sweden): Chalmers Industriteknik (CIT), 1994.
5. Handbook of air pollution from internal combustion engines. Pollutant formation and control;Sher,1998