“Study on Synthesis of Solid Acid Catalyst from Borassus Flabellifer L. Waste With Sulfonation Method: Kajian Sintesis Katalis Asam Padat Dari Limbah Sabut Siwalan (Borassus Flabellifer L.) Dengan Metode Sulfonasi”. 2021. Journal Pharmasci (Journal of Pharmacy and Science) 6 (2): 89-97. https://doi.org/10.53342/pharmasci.v6i2.224.