Shahdan, S.N. and Hirzin, R.S.F.N. 2021. Pre-Treatment of Used Cooking Oil Followed by Transesterification Reaction in the Production of Used Cooking Oil-Based Polyol. Scientific Research Journal. 18, 2 (Aug. 2021), 129–146. DOI:https://doi.org/10.24191/srj.v18i2.13749.