1. Directive 2004/8/EC of the European Parliament and of the Council of 11 February 2004 on the promotion of cogeneration based on a useful heat demand in the internal energy market and amending Directive 92/42/EEC.
2. Muszer T.: Thermo-economical analysis of re-powering of heating plant in high-efficiency cogeneration unit on example of Heating Plant Gliwice. MSc thesis, Silesian University of Technology, Gliwice 2010.