M. Harikumaran Nair and K. Kumari Nisha, “Synthesis and Characterization of Dioxotungsten(VI) Complexes of Azodyes Derived from 1-Phenyl-2,3-dimethyl-4-Amino-5-Pyrazolone”, ajc, vol. 17, no. 3, pp. 1729–1735, May 2016.