@article{siqueira_terra_2004,  title={Nonlinear H<FONT FACE=Symbol>¥</FONT> control for underactuated manipulators with robustness tests},  volume={15},  ISSN={0103-1759},  url={https://doi.org/10.1590/S0103-17592004000300009},  DOI={10.1590/S0103-17592004000300009},  number={3},  journal={Sba: Controle & Automação Sociedade Brasileira de Automatica},  publisher={Sociedade Brasileira de Automática},  author={Siqueira, Adriano A. G. and Terra, Marco Henrique},  year={2004},  month={Jul},  pages={339–350} }