Multiple solutions for elliptic equations involving a general operator   in divergence form
  In this paper, exploiting variational methods, the existence of three weak solutions for a class of elliptic equations involving a general operator in divergence form and with Dirichlet boundary condition is investigated. Several special cases are analyzed. In conclusion, for completeness, a concrete example of an application is presented by finding the existence of three nontrivial weak solutions for an uniformly elliptic second-order problem on a bounded Euclidean domain. 
Giovanni Molica Bisci and Du\v{s}an Repov\v{s}
math.AP