@article{mariani_pêgo-fernandes_2014,  title={Observational studies: why are they so
               important?},  volume={132},  ISSN={1516-3180},  url={https://doi.org/10.1590/1516-3180.2014.1321784},  DOI={10.1590/1516-3180.2014.1321784},  number={1},  journal={Sao Paulo Medical Journal},  publisher={Associação Paulista de Medicina - APM},  author={Mariani, Alessandro Wasum and Pêgo-Fernandes, Paulo Manuel},  year={2014},  pages={01–02} }