Mehta, S.B., and M.K. Shah. “Absorption Difference Spectroscopy of Lysozyme With Nd(III) in Presence of Zn(II), Cd(II), Ca(II) and Mg(II) Involving 4f-4f Transition ”. Asian Journal of Chemistry, vol. 14, no. 1, Mar. 2010, pp. 236-42, https://asianpubs.org/index.php/ajchem/article/view/22001.