Beckman, Jayson, and Getachew Nigatu. “Do Political Factors Influence U.S. Crude Oil Imports?”. International Journal of Energy Economics and Policy 11, no. 4 (June 8, 2021): 288–297. Accessed November 10, 2024. https://econjournals.org.tr/index.php/ijeep/article/view/11238.