Ardan, S. ., A. Putra, L. DJ, R. Sundari, S. B. . Etika, and U. K. Nizar. “THE STUDY OF REUSED SILICA-TITANIA CATALYST ON BIODIESEL PRODUCTION IN VARIOUS REACTION TIMES”. International Journal of Advances in Scientific Research and Engineering (IJASRE), ISSN:2454-8006, DOI: 10.31695/IJASRE, vol. 5, no. 8, Aug. 2019, pp. 133-41, doi:10.31695/IJASRE.2019.33458.