P. dos S. Roldan, I. L. de Alcântara, J. C. Rocha, C. do C. F. Padilha, and P. M. Padilha, “Determination of Copper, Iron, Nickel and Zinc in fuel kerosene by FAAS after adsorption and pre-concentration on 2-aminothiazole-modified silica gel”, Eclet. Quim., vol. 29, no. 2, pp. 33–40, Dec. 2004.