Bapa, Y. and Botahala, L. (2019) “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(2), pp. 104-110. doi: 10.20956/ica.v12i2.7889.