1. Directive 2001/77/WE of the European Parliament and the Councul of 27 September 2001 on the Promotion of Electricity Produced from Renewable Energy Sources in the Internal Electricity Market,2001
2. Biomass as a power raw material (in Polish: biomasa jako surowiec energetyczny);Gutowska,2007
3. Renewable energy sources and possibilities of their practical use (in Polish: Odnawialne źródła energii i możliwości ich praktycznego wykorzystania);Rafał Bal,2006
4. Total Primary Energy Supply (TPES) by Source, World 1990-2017,2020