Rai, B.K., Puja Sinha, S.N. Vidyarthi, and Vineeta Singh. 2011. “Spectroscopic Study of Co(II), Ni(II) and Cu(II) Complexes With Nitrogen and Sulphur Containing Schiff Base Ligands”. Asian Journal of Chemistry 23 (10):4629-31. https://asianpubs.org/index.php/ajchem/article/view/10913.