Hernandez Fernandez F., Perez de los Rios A., Ginesta Anzola A., Sanchez Segado S., Lozano Blanco L., Moreno Sánchez J., Godinez Seoane C., 2010, Use of Ionic Liquids as ‘green’ Solvents for Extraction of Zn2+, Cd2+, Fe3+ and Cu2+ from Aqueous Solutions., Chemical Engineering Transactions, 21, 631-636.