On Nonlinear Eigen-problems of Quasi-linear Elliptic Operators. Journal of Partial Differential Equations, [S. l.], v. 4, n. 3, p. 56–72, 1991. Disponível em: https://staging.gsp.tricubic.dev/jpde/article/view/3687. Acesso em: 18 mar. 2026.