@article{freire_nardi_2012,  title={Panic disorder and the respiratory system: clinical subtype and challenge tests},  volume={34},  ISSN={1516-4446},  url={https://doi.org/10.1590/S1516-44462012000500004},  DOI={10.1590/S1516-44462012000500004},  journal={Brazilian Journal of Psychiatry},  publisher={Associação Brasileira de Psiquiatria},  author={Freire, Rafael C. and Nardi, Antonio E.},  year={2012},  month={Jun},  pages={32–41} }