Chen, Yutong, and Jiabao Su. “Bounded Resonant Problems Driven by Fractional Laplacian”. Topological Methods in Nonlinear Analysis 57, no. 2 (June 2, 2021): 635–661. Accessed April 23, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2020.059.