Gonella, Laura. “Existence of Periodic Solutions for Some Singular Elliptic Equations With Strong Resonant Data”. Topological Methods in Nonlinear Analysis 43, no. 1 (April 12, 2016): 157–170. Accessed March 29, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2014.010.