1. Daniel Hec, Karsten, V. Frederiksen, Terry Williams, Miguel Muñecas, 2000, European initiatives on labelling of central heating gas boilers, LABNET internal report.
2. European Council Directive 92/75/EEC on the indication by labelling and standard product information of the consumption of energy and other resources by household appliances;European Council;Official Journal of the European Communities,1992
3. Directive 2004/8/EC of the improvement of heat power coupling on the basis of demand of useful heat inside the internal market and the change of directive 92/42/EEC;European Council;Publication Magazine of the European Union,2004
4. Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for space heaters and combination heaters.
5. On the indication by labelling and standard product information of the consumption of energy and other resources by energy-related products;European Council;Official Journal of the European Communities,2010