## An infinite class of periodic solutions of periodically perturbed Duffing equations at resonance

- T. R. Ding
- Proc. Amer. Math. Soc
- 1982

@inproceedings{DING2010AGO, title={A Generalization of the Poincar{\'e}-birkhoff Theorem}, author={WEI-YUE DING}, year={2010} }

- Published 2010

A generalized form of the Poincaré-Birkhoff theorem is proved. The generalization is useful for the further applications of this famous fixed point theorem.