Joelianingsih, Joelianingsih, Yuli Amalia Husnil, and Is Sulistyati Purwaningsih. 2018. “Effect of Soybean Biodiesel Addition on the Quality of Palm Stearin Biodiesel”. International Journal of Oil Palm 1 (3):103-9. http://ijop.id/index.php/ijop/article/view/15.