I. Lestari, D. Amalia, W. Prastistho, J. B. P. Angin, and M. H. Zenatik, “Combination Process of Rice Husk Ash Coagulation and Electrocoagulation for Palm Oil Mill Effluent Treatment”, Eksergi, vol. 22, no. 2, pp. 113–119, Jun. 2025.