Ralević, Predrag, Momčilo Dobrodolac, Libor Švadlenka, Dragana Šarac, and Dejan Đurić. “Efficiency and Productivity Analysis of Universal Service Obligation: A Case of 29 Designated Operators in the European Countries”. Technological and Economic Development of Economy 26, no. 4 (June 12, 2020): 785-807. Accessed November 23, 2024. https://tede.vgtu.lt/index.php/TEDE/article/view/12062.