Alguacil, F. J. “The Removal of Toxic Metals from Liquid Effluents by Ion Exchange Resins. Part lll:Copper(ll)/Sulphate/Amberlite 200”. Revista De Metalurgia, vol. 39, no. 3, June 2003, pp. 205-9, doi:10.3989/revmetalm.2003.v39.i3.330.