MUGNAI, D. Resonant nonlinear Neumann problems with indefinite weight. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE, [S. l.], v. 11, n. 4, p. 729-788, 2012. DOI: 10.2422/2036-2145.201012_003. Disponível em: https://journals.sns.it/index.php/annaliscienze/article/view/279. Acesso em: 20 feb. 2026.