KMIT, I. Ya.; PTASHNIK, B. I. Well-posedness of boundary-value problems for multidimensional hyperbolic systems. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 60, n. 2, p. 192–203, 2008. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3149. Acesso em: 6 dec. 2025.