@article{ferreira_abramof_motisuke_rappl_closs_ueta_boschetti_bandeira_1999,  title={Band crossing evidence in PbSnTe observed by optical transmission measurements},  volume={29},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97331999000400033},  DOI={10.1590/S0103-97331999000400033},  number={4},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Ferreira, S. O. and Abramof, E. and Motisuke, P. and Rappl, P. H. O. and Closs, H. and Ueta, A. Y. and Boschetti, C. and Bandeira, I. N.},  year={1999},  month={Dec},  pages={771–774} }