1. European Environmental Agency. Air Quality in Europe—2015 Report (EEA Report No. 5/2015). https://op.europa.eu/en/publication-detail/-/publication/9f0ff3b5-a4a5-11e5-b528-01aa75ed71a1/language-en
2. European Commission. Commission Regulation 692/2008 of 18 July 2008 Implementing and Amending Regulation (EC) No. 715/2007 of the European Parliament and of the Council on Type-approval of Motor Vehicles with Respect to Emissions from Light Passenger and Commercial Vehicles.
3. International Energy Agency (2017) CO2 Emissions from Fuel Combustion. International Energy Agency, Paris.
4. Controlling carbon monoxide emissions from automobile vehicle exhaust using copper oxide catalysts in a catalytic converter
5. Possibilities and Constraints for Lightweight in Exhaust Systems