Mbangala, Augustin Mapapa, Sergio Perelman, and Achraf Tarsim. “Sub Saharan Railway Firms: Reforms and Demand Effects on Technical Efficiency - A Stochastic Frontier Analysis Between 1995 and 2005”. Journal of Applied Business and Economics 22, no. 9 (December 3, 2020). Accessed July 7, 2024. https://mail.articlegateway.com/index.php/JABE/article/view/3687.