Hendrawan, Riko, Gayuh T Permana, and Kristian WA Nugroho. “Efficiency Analysis of Telecommunications Companies in Southeast Asia Using Stochastic Frontier Analysis (SFA) Method”. Jurnal Siasat Bisnis 23, no. 2 (November 11, 2019): 104–112. Accessed November 24, 2024. https://journal.uii.ac.id/JSB/article/view/12076.