Nontrivial solutions for a nonlinear discrete elliptic equation with periodic boundary conditions.

Liang Bai Guang Zhang Nontrivial solutions for a nonlinear discrete elliptic equation with periodic boundary conditions. 321-333 2009 210 Applied Mathematics and Computation 2 http://dx.doi.org/10.1016/j.amc.2008.12.024 db/journals/amc/amc210.html#BaiZ09