de Castro, G. R.; Padilha, C. do C. F.; Rocha, J. C.; Valente, J. P. S.; Florentino, A. de O.; Padilha, P. M. Lability of Cd, Cr, Cu, Mn and Pb Complexed by Aquatic Humic Substances. Eclet. Quim. 2005, 30, 45-51.