Marlina, R., A. Oktasari, and R. Rohmatullaili. “Utilization of Adsorbent Cocoa Shell For Purification of Used Cooking Oil”. Stannum : Jurnal Sains Dan Terapan Kimia, Vol. 4, no. 1, May 2022, pp. 6-12, doi:10.33019/jstk.v4i1.2638.