SUNDARAMOORTHI, P., and S. KALAINATHAN. “Growth of CaHPO4 Crystals in Silica Gel Media and Its Characterization Studies, Nucleation Reduction Process”. Asian Journal of Chemistry, vol. 20, no. 1, Mar. 2010, pp. 287-94, https://asianpubs.org/index.php/ajchem/article/view/19406.