@article{cavalheiro_zaghete_paiva-santos_varela_2002,  title={Effect of the Addition of Potassium or Lithium on the Columbite Precursor Microstructure},  volume={5},  ISSN={1516-1439},  url={https://doi.org/10.1590/S1516-14392002000400002},  DOI={10.1590/S1516-14392002000400002},  number={4},  journal={Materials Research},  publisher={ABM, ABC, ABPol},  author={Cavalheiro, Alberto A. and Zaghete, Maria A. and Paiva-Santos, Carlos O. and Varela, José A.},  year={2002},  month={Oct},  pages={399–404} }