et. al, Muhammad Akram Adnan. “Empirical Study of Speed Characteristics at Sag Vertical Curve for Two-Lane Rural Highway”. International Journal of Advanced Science and Technology 29, no. 2 (January 13, 2020): 1342 - 1352. Accessed July 23, 2024. https://sersc.org/journals/index.php/IJAST/article/view/3374.