Ibrahim, Muhammad Akram Ramadhan, Nor Izzati Jaini, and Hafizah Bahaludin. “ A Study of Oil and Gas Producers Subsector Portfolio Using the Trade-off Ranking Method”. Yugoslav Journal of Operations Research 35, no. 1 (June 10, 2024): 69–84. Accessed July 28, 2025. https://yujor.erc.fon.bg.ac.rs/index.php/yujor/article/view/818.