Liu, Hai-Xing, et al. “Synthesis and Crystal Structure of Phosphorus Vanadium Heteropoly Acid Potassium Compound: (K12P4V72O172)·24Cl·24(OH)&Middot;14.4H2O”. Asian Journal of Chemistry, vol. 25, no. 14, Aug. 2013, pp. 8217-8, doi:10.14233/ajchem.2013.14607.