Airlangga, T. A., N. Matsue, E. Hanudin, and E. Johan. “Phosphate Adsorption Capacity of Allophane from Two Volcanic Mountains in Indonesia”. JOURNAL OF TROPICAL SOILS, vol. 25, no. 1, Jan. 2020, pp. 39-46, doi:10.5400/jts.2020.v25i1.39-46.