Dalagan, J. Q., and R. A. Ibale. “Adsorption Behavior of Heavy Metal Ions (Cr3+, Pb2+ and Cu2+) Into Magnetite-Graphite Oxide-Diatomite”. Asia Pacific Higher Education Research Journal (APHERJ), vol. 3, no. 1, Aug. 2016, https://po.pnuresearchportal.org/ejournal/index.php/apherj/article/view/211.