@article{mazzafera_1999,  title={Mineral nutrition and caffeine content in coffee leaves},  volume={58},  ISSN={0006-8705},  url={https://doi.org/10.1590/S0006-87051999000200018},  DOI={10.1590/S0006-87051999000200018},  number={2},  journal={Bragantia},  publisher={Instituto Agronômico de Campinas},  author={MAZZAFERA, PAULO},  year={1999},  pages={387–391} }