Nyoni, Bothwell, and Andrew Phiri. “The Electricity-Growth Nexus in South Africa: Evidence from Asymmetric Cointegration and Co-Feature Analysis”. International Journal of Energy Economics and Policy, vol. 8, no. 6, Oct. 2018, pp. 80-88, https://econjournals.org.tr/index.php/ijeep/article/view/6626.