Zailan, Z., Ali, H., Chau, J. W., Jusoh, M., Tahir, M., & Zakaria, Z. Y. (2020). Development of Sulphonated Sago Pith Waste Catalyst for Esterification of Palm Fatty Acid Distillate to Methyl Ester. Chemical Engineering Transactions, 78, 31-36. https://doi.org/10.3303/CET2078006