Motreanu, Dumitru, Viorica V.Motreanu, and Nikolaos S.Papageorgiou. 2011. “Multiple Constant Sign and Nodal Solutions for Nonlinear Neumann Eigenvalue Problems”. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE 10 (3):729-55. https://doi.org/10.2422/2036-2145.2011.3.09.