1. The European Commission, Energy Efficiency: Delivering the 20% Target COM, 2008 (2008).
2. The European Commission, Directive 2012/27/EU on energy efficiency, 2012.
3. WWF, Living Planet Report 2014, 2014.
4. International Energy Agency (IEA), Key World Energy Statistics 2014, 2014.
5. The European Commission, Directive 2010/31/EU on the energy performance of buildings, 2010.