LAVRENYUK, S. P.; PROTSAKH, N. P. Mixed Problem for an Ultraparabolic Equation in Unbounded Domain. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 54, n. 8, p. 1053–1066, 2002. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4146. Acesso em: 6 dec. 2025.