@article{almeida_moreira_santos_1998,  title={On the Ziglin-Yoshida analysis for some classes of homogeneous hamiltonian systems},  volume={28},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97331998000400022},  DOI={10.1590/S0103-97331998000400022},  number={4},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Almeida, M. A. and Moreira, I. C. and Santos, F. C.},  year={1998},  month={Dec},  pages={470–480} }