DUEÑAS-MORENO, J.; PÉREZ-REGALADO FUENTES, J.; MENÉNDEZ-GUTIÉRREZ, C.; PEREDA-REYES, I. Bioadsorption of Cu2+, Ni2+, Zn2+ and Pb2+ using an activated sludge process. Chemical Technology, v. 38, n. 3, p. 732-749, 6 set. 2018.