@article{calixto_2019,  title={The role of natural products in modern drug discovery.},  volume={91},  ISSN={0001-3765},  url={https://doi.org/10.1590/0001-3765201920190105},  DOI={10.1590/0001-3765201920190105},  journal={Anais da Academia Brasileira de Ciências},  publisher={Academia Brasileira de Ciências},  author={CALIXTO, JOÃO B.},  year={2019},  pages={e20190105} }