S. Samion, M. R. Daud, N. Sapawe, and A. Yahya. “An Investigation of Hard-on-Soft Sliding Contact Using Palm Fatty Acid Distillate”. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, vol. 2, no. 1, Oct. 2014, https://semarakilmu.com.my/journals/index.php/fluid_mechanics_thermal_sciences/article/view/2522.