ALLERGRETTO, Walter; NISTRI, Paolo. Elliptic equations with discontinuous nonlinearities. Topological Methods in Nonlinear Analysis, [S. l.], v. 2, n. 2, p. 233–251, 1993. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1993.041. Acesso em: 8 jul. 2025.