@article{Gonella_2016, title={Existence of periodic solutions for some singular elliptic equations with strong resonant data}, volume={43}, url={https://apcz.umk.pl/TMNA/article/view/TMNA.2014.010}, abstractNote={We prove the existence of at least one $T$-periodic solution $(T> 0)$ for differential equations of the form $$ \left(\frac{uā€™(t)}{\sqrt{1-{uā€™}^2(t) }\right)ā€™ =f(u(t))+h(t),\quad \text{in } (0,T), $$ where $f$ is a continuous function defined on $\mathbb{R}$ that satisfies a {\it strong resonance condition}, $h$ is continuous and with zero mean value. Our method uses variational techniques for nonsmooth functionals.}, number={1}, journal={Topological Methods in Nonlinear Analysis}, author={Gonella, Laura}, year={2016}, month={Apr.}, pages={157ā€“170} }