Butkevicius, Saulius, et al. “Evaluation of Flexible Road Pavement Construction State Using Objective Strength Criteria”. The Baltic Journal of Road and Bridge Engineering, vol. 2, no. 2, June 2007, pp. 61-66, https://bjrbe-journals.rtu.lv/bjrbe/article/view/1822-427X.2007.2.61%E2%80%9366.