ZINE, A.M., et al. “PH Metric Study of Ternary Complexes of Co(II) With Mercaptosuccinic Acid, 2-Mercaptopropionyl Glycine and Amino Acids”. Asian Journal of Chemistry, vol. 19, no. 6, Mar. 2010, pp. 4385-9, https://asianpubs.org/index.php/ajchem/article/view/19924.