@article{tsallis_2008,  title={My friend Ricardo Ferreira, an impressive natural philosopher},  volume={19},  ISSN={0103-5053},  url={https://doi.org/10.1590/S0103-50532008000200002},  DOI={10.1590/S0103-50532008000200002},  number={2},  journal={Journal of the Brazilian Chemical Society},  publisher={Sociedade Brasileira de Química},  author={Tsallis, Constantino},  year={2008},  pages={203–205} }