Gradziuk P. Economic Efficiency of Photovoltaic Installations (A Case Study at the Zwierzyniec–Biały Słup Research and Education Centre of Roztocze National Park). br [Internet]. 2015 Feb. 23 [cited 2024 Nov. 8];12(4):117-22. Available from: https://czaz.akademiazamojska.edu.pl/index.php/br/article/view/989