“Concentration Effect of MgO/K2O Catalyst on Transesterification of Castor Seed (Ricinus communis) Oil: Pengaruh Konsentrasi Katalis MgO/K2O pada Transesterifikasi Minyak Biji Jarak (Ricinus communis)”, Stannum, vol. 6, no. 2, pp. 96–103, Oct. 2024, doi: 10.33019/jstk.v6i2.4692.