R. D. Wirahadikusumah, .-. Sapitri, B. Susanti, and B. W. Soemardi, “Risk in Government’s Estimate for Toll Road: Based on Investors’ Perspective”, Int. J. Adv. Sci. Eng. Inf. Technol., vol. 8, no. 2, pp. 475–482, Mar. 2018.