Ramos Real, F.J., and B. Tovar. “Revisiting Electric utilities’ Efficiency in the Southern African Power Pool, 1998–2009”. Journal of Energy in Southern Africa 31, no. 1 (February 26, 2020): 1–13. Accessed July 22, 2024. https://journals.assaf.org.za/index.php/jesa/article/view/7670.