Artemkina, Liya R., Natalya Y. Sopilko, Olga Y. Myasnikova, Irina U. Eremina, Nataliya V. Bondarchuk, and Sergey V. Shamsheev. “The Model of Upstream Investment Portfolio in the Mature Regions”. International Journal of Energy Economics and Policy 9, no. 4 (June 1, 2019): 173–180. Accessed November 9, 2024. https://econjournals.org.tr/index.php/ijeep/article/view/7965.