@article{magalhães_fonseca_nemes_2006,  title={Thouless theorem for one and two degrees of freedom},  volume={28},  ISSN={1806-1117},  url={https://www.scielo.br/j/rbef/a/Mnp7KfcFGXpPwgY6HctxtJk/},  number={2},  journal={Revista Brasileira de Ensino de Física},  publisher={Sociedade Brasileira de Física - SBF},  author={Magalhães, A.R. Bosco de and Fonseca, C.H. d'Àvila and Nemes, M.C.},  year={2006},  month={Apr},  pages={161–166} }