Putro, Ledis Heru Saryono. 2021. “Emissions of CH4 and CO2 from Wastewater of Palm Oil Mills: A Real Contribution to Increase the Greenhouse Gas and Its Potential As Renewable Energy Sources: 10.32526/Ennrj/20/202100149”. Environment and Natural Resources Journal 20 (1). Nakhon Pathom, Thailand:61-72. https://ph02.tci-thaijo.org/index.php/ennrj/article/view/245510.