Duga, N. D. F., P. E. A. Imperial, A. N. Soriano, and A. D. Nieva. “Packed Bed Biosorption of Lead and Copper Ions Using Sugarcane Bagasse”. ASEAN Journal of Chemical Engineering, Vol. 16, no. 1, June 2016, pp. 23-37, https://journal.ugm.ac.id/v3/AJChE/article/view/8905.