1. On a class of nonlinear Dirichlet problems with multiple solutions;Ambrosetti;Nonlinear Anal.,1984
2. Sharp nonuniqueness results for some nonlinear problems;Ambrosetti;Nonlinear Anal.,1979
3. Simplicité et isolation de la première valeur propre du p-Laplacien avec poids;Anane;C. R. Acad. Sci. Paris r. I Math.,1987
4. Nonlinear Differential Equations in Ordered Spaces;Carl,2000
5. Nonsmooth variational problems and their inequalities;Carl,2007