El-Ajaily, M.M., et al. “Synthesis and Characterization of Some Co(II), Ni(II) and Cu(II) Mixed Ligand Chelates of 8-Hydroxyquinoline, Anthranilic Acid and O-Aminophenol”. Asian Journal of Chemistry, vol. 18, no. 4, Mar. 2010, pp. 2421-6, https://asianpubs.org/index.php/ajchem/article/view/20595.