Hajiyev, N., Mansura, M., Sverdlikova, E., Safronov, R., & Vityutina, T. (2021). Oligopoly Trends in Energy Markets: Causes, Crisis of Competition, and Sectoral Development Strategies. International Journal of Energy Economics and Policy, 11(6), 392–400. Retrieved from https://www.econjournals.com/index.php/ijeep/article/view/11634