1. European Parliament and Council. Directive 2004/8/EC “promotion of cogeneration based on a useful heat demand in the internal energy market”. Off J Eur Union 2004; L52: 50–60 [21.02.2004].
2. European Parliament and Council. Decision 2008/952/EC “establishing detailed guidelines for the implementation and application of Annex II to Directive 2004/8/EC of the European Parliament and of the Council”. Off J Eur Union 2008; L388: 55–61 [17.12.2008].
3. European Parliament and Council. Decision 2011/877/EU “Establishing harmonised efficiency reference values for separate production of electricity and heat in application of Directive 2004/8/EC of the European Parliament and of the Council and repealing Commission Decision 2007/74/EC”. Off J Eur Union 2011; L343: 91–96 [23.12.2011].
4. European Commission. EU ENERGY in figures – pocketbook 2013. Publications Office of the European Union; 2013. .
5. Lapillonne B, Pollier K. Energy efficiency trends for households in the EU. Publication of the ODYSSEE-MURE Project; January 2014. .