Sumatri, I., H. Hadiyanto, S. Suherman, and M. Christwardana. “Production of Biodiesel Using Enzymatic Esterification of Multi-Feedstock Oils”. ASEAN Journal of Chemical Engineering, Vol. 23, no. 2, Aug. 2023, pp. 194-09, https://journal.ugm.ac.id/v3/AJChE/article/view/9745.