@article{oliveira_souza_borges_osório_1999,  title={Cyclotron mass of electrons in GaN-Al xGa1-xN heterostructures},  volume={29},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97331999000400011},  DOI={10.1590/S0103-97331999000400011},  number={4},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Oliveira, Solemar Silva and Souza, Marcio Adriano R. and Borges, Antonio Newton and Osório, Francisco A. Pinto},  year={1999},  month={Dec},  pages={675–678} }