Bonanno, Gabriele, and Salvatore A. Marano. “Positive Solutions of Elliptic Equations With Discontinuous Nonlinearities”. Topological Methods in Nonlinear Analysis 8, no. 2 (December 1, 1996): 263–273. Accessed July 22, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.1996.032.