Haryanto, Agus, Shintawati Shintawati, and Udin Hasanudin. 2021. “Anaerobic Treatment for Palm Oil Mill Effluent Using Covered In-the Ground Anaerobic Reactor (CIGAR)”. Journal of Engineering and Technological Sciences 53 (6):210609. https://doi.org/10.5614/j.eng.technol.sci.2021.53.6.9.