@article{morais_scalvi_geraldo_ribeiro_santilli_2003,  title={Er rare-earth ion incorporation in sol-gel SnO2},  volume={6},  ISSN={1516-1439},  url={https://doi.org/10.1590/S1516-14392003000400003},  DOI={10.1590/S1516-14392003000400003},  number={4},  journal={Materials Research},  publisher={ABM, ABC, ABPol},  author={Morais, Evandro Augusto and Scalvi, Luis Vicente de Andrade and Geraldo, Viviany and Ribeiro, Sidney José Lima and Santilli, Celso Valentim},  year={2003},  month={Oct},  pages={445–449} }