FOURNIER, Gilles; TIMOUMI, M; WILLEM, Michael. The limiting case for strongly indefinite functionals. Topological Methods in Nonlinear Analysis, [S. l.], v. 1, n. 2, p. 203–209, 1993. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1993.015. Acesso em: 4 jul. 2025.