Haryanto, Iman, and Osamu Takahashi. 2007. “Effect of Aggregate Gradation on Workability of Hot Mix Asphalt Mixtures”. The Baltic Journal of Road and Bridge Engineering 2 (1): 21-28. https://bjrbe-journals.rtu.lv/bjrbe/article/view/1822-427X.2007.1.21%E2%80%9328.