@article{guzmán_2011,  title={Entrenamiento del vibrato en cantantes},  volume={13},  ISSN={1516-1846},  url={https://doi.org/10.1590/S1516-18462010005000072},  DOI={10.1590/S1516-18462010005000072},  number={3},  journal={Revista CEFAC},  publisher={ABRAMO Associação Brasileira de Motricidade Orofacial},  author={Guzmán, Marco Antonio},  year={2011},  month={May},  pages={568–578} }