Costa, D. G. and Cuesta, M. (1996) “Existence results for resonant perturbations of the Fučik spectrum”, Topological Methods in Nonlinear Analysis, 8(2), pp. 295–314. Available at: https://apcz.umk.pl/TMNA/article/view/TMNA.1996.034 (Accessed: 22 July 2024).