S. ., H. Husin, and M. ., “Organosolv Pretreatment Process and Hydrolysis Acid Conversion Oil Palm Frond (OPF) as Bioetanol Raw Material”, IJET, vol. 7, no. 4, pp. 6063–6065, May 2019, doi: 10.14419/ijet.v7i4.19539.