Rao, G., N. Kumar, T. Rao, K. Rao, and N. V. Simhadri. “Chemical Speciation of Binary Complexes of Pb(Ii), Cd(Ii) and Hg(Ii) With L-Methionine in Propylene Glycol -Water Mixture”. Journal of Progressive Research in Chemistry, Vol. 2, no. 1, July 2015, pp. 61-68, http://scitecresearch.com/journals/index.php/jprc/article/view/186.