Subotić, Marko, Željko Stević, Edis Softić, and Veljko Radičević. “Passenger Car Equivalents on Downgrades of Two-Lane Roads”. The Baltic Journal of Road and Bridge Engineering 15, no. 4 (September 28, 2020): 152–173. Accessed June 14, 2024. https://bjrbe-journals.rtu.lv/bjrbe/article/view/bjrbe.2020-15.499.