A class of nonlinear elliptic problems driven by -Laplacian-like with a nonsmooth locally Lipschitz potential was considered. Applying the version of a nonsmooth three-critical-point theorem, existence of three solutions of the problem is proved.
"Three Solutions for Inequalities Dirichlet Problem Driven by -Laplacian-Like." Abstr. Appl. Anal. 2013 (SI29) 1 - 6, 2013. https://doi.org/10.1155/2013/575328