Моллов, Йордан. “ENERGY PRODUCTION FROM RENEWABLE SOURCES IN THE REPUBLIC OF BULGARIA – SITUATION AND TRENDS”. Modern engineering and innovative technologies 1, no. 02-01 (November 30, 2017): 48–52. Accessed May 17, 2024. https://www.moderntechno.de/index.php/meit/article/view/meit02-01-012.