@article{santos_hartmann_2021,  title={Chemical classification of common volcanic rocks based on degree of silica saturation and CaO/K<sub>2</sub>O ratio},  volume={93},  ISSN={0001-3765},  url={https://doi.org/10.1590/0001-3765202120201202},  DOI={10.1590/0001-3765202120201202},  number={3},  journal={Anais da Academia Brasileira de Ciências},  publisher={Academia Brasileira de Ciências},  author={SANTOS, JOÃO O.S. and HARTMANN, LÉO A.},  year={2021},  pages={e20201202} }