Bogoviz, Aleksei V., et al. “A Quantitative Analysis of Energy Security Performance by Brazil, Russia, India, China, and South Africa in 1990-2015”. International Journal of Energy Economics and Policy, vol. 9, no. 3, Apr. 2019, pp. 244-50, https://econjournals.net.tr/index.php/ijeep/article/view/7585.