Ralević P, Dobrodolac M, Švadlenka L, Šarac D, Đurić D. Efficiency and productivity analysis of universal service obligation: a case of 29 designated operators in the European countries. TEDE [Internet]. 2020Jun.12 [cited 2024Nov.23];26(4):785-807. Available from: https://jau.vgtu.lt/index.php/TEDE/article/view/12062