. Triyono, W. Trisunaryanti, A. D. Putri, A. Lutfiana, and K. Dewi, “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”, ajc, vol. 30, no. 5, pp. 953–957, Mar. 2018.