In this paper we study the existence of nontrivial critical points. As applications, we study the existence of nontrivial solutions of the Dirichelet problem for nonlinear elliptic PDE and periodic boundary value problem for nonlinear OPE. © 1992.
Shujie, L., & Liu, J. Q. (1992). Nontrivial critical points for asymptotically quadratic function. Journal of Mathematical Analysis and Applications, 165(2), 333–345. https://doi.org/10.1016/0022-247X(92)90044-E