1. BP annual report,2016
2. European Parliament and Council Directive 2002/91/CE on the energy performance of buildings. Available online: https://eur-lex.europa.eu/legal-content/LVN/TXT/?uri=celex:32002L0091 (accessed on 04 07 2018).
3. European Parliament and Council Directive 2010/31/UE on the energy performance of buildings. Available online: https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32010L0031 (accessed on 04 07 2018).
4. European Parliament and the Council Directive 2018/844/EU of 30 May 2018 amending Directive 2010/31/EU on the energy performance of buildings and Directive 2012/27/EU on energy efficiency. Available online: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32018L0844&from=EN (accessed on 18 10 2018).