Dolak, Ibrahim, et al. “Removal and Preconcentration of Pb(II), Cr(III), Cr(VI) from the Aqueous Solution and Speciation of Cr(III)-Cr(VI) by Using Functionalized Amberlite XAD-16 Resin With Dithioethylenediamine”. Asian Journal of Chemistry, vol. 22, no. 8, June 2010, pp. 6117-24, https://asianpubs.org/index.php/ajchem/article/view/11790.