Life-span of Classical Solutions to Nonlinear Wave Equations in Two-space-dimensions II. Journal of Partial Differential Equations, [S. l.], v. 6, n. 1, p. 17–38, 1993. Disponível em: https://global-sci.com/index.php/jpde/article/view/3733. Acesso em: 5 dec. 2025.