1. Fact sheet: diesel exhaust in the United States;United States Environmental Protection Agency,2003
2. European Union council directive of 3 December 1987 on the approximation of the laws of the Member States relating to the measures to be taken against the emission of gaseous and particulate pollutants from diesel engines for use in vehicles;Council of the European Communities,1988
3. Directive 1999/96/EC of the European parliament and of the council of 13 December 1999;Council of the European Communities,1999
4. Regulation (EC) No 595/2009 of 18 June 2009;European Parliament and the Council of the European Union,2009
5. DieselNet. http://www.dieselnet.com/; 2009.