Muhammad Arif Dandan, Wan Mohamad Aiman Wan Yahaya, and Syahrullail Samion. 2018. “The Effect of Fluidity of Palm Kernel Oil With Pour Point Depressant on Coefficient Of Friction Using Fourball Tribotester”. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 50 (2):97-107. https://semarakilmu.com.my/journals/index.php/fluid_mechanics_thermal_sciences/article/view/2836.