Kumar Singh, Sudesh, and C.P. Chandel. “Polarographic Studies on Mixed-Ligand Complexes of Lead(II) With DL-3-(3-,4-Dihydroxy Phenyl) Alanine and Some Dicarboxylic Acids”. Asian Journal of Chemistry, vol. 13, no. 3, Mar. 2010, pp. 1137-41, https://asianpubs.org/index.php/ajchem/article/view/22750.