MAEDA, F.-Y.; ONO, T. Perturbation theory for nonlinear Dirichlet problems. Annales Fennici Mathematici, [S. l.], v. 28, n. 1, p. 207–222, 2003. Disponível em: https://afm.journal.fi/article/view/135074. Acesso em: 16 may. 2024.