MOTREANU, D.; V.MOTREANU, V.; S.PAPAGEORGIOU, N. Multiple Constant Sign and Nodal Solutions for Nonlinear Neumann Eigenvalue Problems. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE, [S. l.], v. 10, n. 3, p. 729-755, 2011. DOI: 10.2422/2036-2145.2011.3.09. Disponível em: http://20.103.181.36/index.php/annaliscienze/article/view/249. Acesso em: 28 may. 2025.