Sitompul, Sabat Okta Ceria, and Risfidian Mohadi. “Preparation of Calcium Oxide from Cattle Bones As Catalyst for Conversion of Waste Cooking Oil to Biodiesel”. Science and Technology Indonesia 2, no. 3 (July 8, 2017): 76–79. Accessed June 5, 2026. https://sciencetechindonesia.com/index.php/jsti/article/view/29.