Shahdan, Siti Nurzubaida, and Radin Siti Fazlina Nazrah Hirzin. “Pre-Treatment of Used Cooking Oil Followed by Transesterification Reaction in the Production of Used Cooking Oil-Based Polyol”. Scientific Research Journal 18, no. 2 (August 27, 2021): 129–146. Accessed January 5, 2025. https://journal.uitm.edu.my/ojs/index.php/SRJ/article/view/3044.