singh, Lakshman, and Ms. Upma Singh. “Synthesis and Charcterization of Oxoyanadium(IV) Coordination Compounds Derived from 4[N-(4-Hydroxy-3-Methyl Benzalidene) Amino] Antipyrine Semicarbazone and 4[N-(3,4,5-Trimethoxybenzalidene) Amino] Antipyrine Semicarbazone&Dagger”;. Asian Journal of Chemistry, vol. 13, no. 4, Mar. 2010, pp. 1427-34, https://asianpubs.org/index.php/ajchem/article/view/22820.