@article{fagundes_2002,  title={Exploring the global topology of the universe},  volume={32},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97332002000500012},  DOI={10.1590/S0103-97332002000500012},  number={4},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Fagundes, Helio V.},  year={2002},  month={Dec},  pages={891–894} }