@article{villa_sinou_thouverez_2007,  title={Investigation of a rotor- bearing system with bearing clearances and hertz contact by using a harmonic balance method},  volume={29},  ISSN={1678-5878},  url={https://doi.org/10.1590/S1678-58782007000100003},  DOI={10.1590/S1678-58782007000100003},  number={1},  journal={Journal of the Brazilian Society of Mechanical Sciences and Engineering},  publisher={Associação Brasileira de Engenharia e Ciências Mecânicas - ABCM},  author={Villa, Cristiano V. S. and Sinou, Jean-Jacques and Thouverez, Fabrice},  year={2007},  month={Jan},  pages={14–20} }