Astuti, W., I. M. Bendiyasa, E. T. Wahyuni, dan A. Prasetya. The Effect of Coal Fly Ash Crystallinity Toward Methyl Violet Adsorption Capacity. Vol. 10, no. 1, Desember 2010, hlm. 8-13, https://jurnal.ugm.ac.id/v3/AJChE/article/view/8061.