Sari M A, Y., and M. D. Situngkir. “Thermal Stability of Polyoxometalate Compound of Keggin K8[2-SiW11O39]∙nH2O Supported With SiO2”. Science and Technology Indonesia, vol. 1, no. 1, June 2017, pp. 8-15, doi:10.26554/sti.2016.1.1.8-15.