Razon, L. F., C. M. Salazar, H. Niiyama, and L. T. N. Doan. “Preparation and Activity of Precipitated Ni-MgO/Al2O3 Catalysts for the Partial Oxidation of Methane”. ASEAN Journal of Chemical Engineering, Vol. 7, no. 2, Dec. 2007, pp. 108-9, https://dev.journal.ugm.ac.id/v3/AJChE/article/view/7683.