ALDASHEV, S. A. Correctness of multi-dimensional Darboux problems for the wave equation. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 45, n. 9, p. 1299–1306, 1993. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5933. Acesso em: 11 apr. 2025.