A. Konstanciak (2018). ALTERNATIVE ENERGY SOURCES USED IN POLAND. SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings; 18th International Multidisciplinary Scientific GeoConference SGEM2018, Ecology, Economics, Education and Legislation, 27-34. https://doi.org/10.5593/sgem2018/5.3/s28.004