Alpi, M. F., J. Januri, and P. R. Ramadhan. “Determinants of Toll Revenues: The Case of PT. Jasa Marga (Belmera Branch) Medan”. Proceeding UII-ICABE, vol. 1, no. 1, Feb. 2020, pp. 355-64, https://journal.uii.ac.id/icabe/article/view/14815.