A. A. Ishak, “Optimization Process for Esterification of Rubber Seed Oil (RSO) With Trimethylolpropane (TMP)”, jst, vol. 5, no. 1, Jul. 2013, Accessed: Mar. 12, 2026. [Online]. Available: https://penerbit.uthm.edu.my/ojs/index.php/JST/article/view/437