@article{padilha_rocha_campos_moreira_federici_1997,  title={Pre-concentration of Cd(II), Cr(III), Cu(II) and Ni(II) on a column packed with free carboxymethylcellulose (CMCH)},  volume={8},  ISSN={0103-5053},  url={https://doi.org/10.1590/S0103-50531997000400003},  DOI={10.1590/S0103-50531997000400003},  number={4},  journal={Journal of the Brazilian Chemical Society},  publisher={Sociedade Brasileira de Química},  author={Padilha, Pedro de Magalhães and Rocha, Julio Cesar and Campos, Joaquim T.S and Moreira, José Celso and Federici, Cilene C},  year={1997},  pages={333–337} }