Nazaruddin Sinaga, Syukran Bestari Nasution, and Maizirwan Mel. 2018. “Process Optimization of Biogas Production from Palm Oil Mill Effluent: A Case Study of a Crude Palm Oil Factory in Muaro Jambi, Indonesia”. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 49 (2):155-69. https://semarakilmu.com.my/journals/index.php/fluid_mechanics_thermal_sciences/article/view/2839.