Triyono, . et al. 2018. Transesterification of Waste Cooking Oil Using NH2/MCM-41 Base Catalyst: Effect of Methanol/Oil Mole Ratio and Catalyst/Oil Weight Ratio towards Conversion of Ester. Asian Journal of Chemistry. 30, 5 (Mar. 2018), 953–957. DOI:https://doi.org/10.14233/ajchem.2018.20979 .