ELEEV, V. A. Boundary-value problems for charged hyperbolic-parabolic equations with characteristic line of changing type. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 47, n. 12, p. 1639–1652, 1995. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5557. Acesso em: 5 dec. 2025.