Rai, B.K., and Bimal Kumar. “Synthesis and Characterization of Ni(II), Cu(II) and Co(II) Complexes With Bidentate Schiff Base Ligand Derived from 2,3,4,5-Tetrahydro indeno[1,2- d]thiazolo[3,2-a][1,3]pyrimidine-11(H)-One”. Asian Journal of Chemistry, vol. 23, no. 10, Aug. 2011, pp. 4635-7, https://asianpubs.org/index.php/ajchem/article/view/10915.