NIZHNIK, L. P.; TARASOV, V. G. Scattering problem for a multidimensional system of first-order partial differential equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 51, n. 8, p. 1065–1076, 1999. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4697. Acesso em: 5 dec. 2025.