1. Estimates near the boundary for solutions of elliptic partial differential equations satisfying general boundary conditions;Agmon;Comm. Pure Appl. Math.,1959
2. Nonlinear eigenvalue problems having precisely two solutions;Amann;Math. Z.,1976
3. Positive solutions of convex nonlinear eigenvalue problems;Amann;Indiana Univ. Math. J.,1976
4. On the exact number of positive solutions of convex nonlinear problems;Ambrosetti;Boll. Un. Mat. Ital.,1978
5. On the existence of multiple solutions for a class of nonlinear boundary value problems;Ambrosetti,1973