“Effect Of The Contact Time Of Candlenut Shell Charcoal And H3PO4 Activator As On The Purification Process Of Used Cooking Oil”. Jurnal Akta Kimia Indonesia (Indonesia Chimica Acta) 12, no. 2 (December 10, 2019): 104–110. Accessed August 18, 2026. https://journal.unhas.ac.id/index.php/ica/article/view/7889.