1. Some applications of monotone operator theory to resonance problems;Amann, Herbert;Nonlinear Anal.,1979
2. Nontrivial solutions for a class of nonresonance problems and applications to nonlinear differential equations;Amann, H.;Ann. Scuola Norm. Sup. Pisa Cl. Sci. (4),1980
3. Multiple periodic solutions for a class of nonlinear autonomous wave equations;Amann, H.;Houston J. Math.,1981
4. Recent advances in the study of the existence of periodic orbits of Hamiltonian systems;Ambrosetti, Antonio,1983
5. Solutions of minimal period for a class of convex Hamiltonian systems;Ambrosetti, Antonio;Math. Ann.,1981