Liu, Jiaquan, Xiang-Qing Liu, and Zhi-Qiang Wang. “Existence Theory for Quasilinear Elliptic Equations via a Regularization Approach”. Topological Methods in Nonlinear Analysis 50, no. 2 (September 23, 2017): 469–487. Accessed January 17, 2022. https://apcz.umk.pl/TMNA/article/view/TMNA.2017.008.