PEJSACHOWICZ, J. Index bundle, Leray-Schauder reduction and bifurcation of solutions of nonlinear elliptic boundary value problems. Topological Methods in Nonlinear Analysis, [S. l.], v. 18, n. 2, p. 243–267, 2001. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2001.033. Acesso em: 26 apr. 2024.