Agwu, George Abuchi, et al. “The Economic Costs of Unsupplied Electricity in Nigeria’s Industrial Sector: The Roles of Captive Power Generation and Firm Characteristics”. International Journal of Energy Economics and Policy, vol. 9, no. 3, Apr. 2019, pp. 196-04, https://econjournals.com/index.php/ijeep/article/view/7681.