@article{bourotte_bertolo_almodovar_hirata_2009,  title={Natural occurrence of hexavalent chromium in a sedimentary aquifer in Urânia, State of São Paulo, Brazil},  volume={81},  ISSN={0001-3765},  url={https://doi.org/10.1590/S0001-37652009000200009},  DOI={10.1590/S0001-37652009000200009},  number={2},  journal={Anais da Academia Brasileira de Ciências},  publisher={Academia Brasileira de Ciências},  author={Bourotte, Christine and Bertolo, Reginaldo and Almodovar, Marta and Hirata, Ricardo},  year={2009},  month={Jun},  pages={227–242} }