ZARUBIN, A. N. Integral representation of a solution of the Cauchy problem for a degenerating hyperbolic equation with retarded argument. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 10, p. 1332–1336, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5131. Acesso em: 14 apr. 2025.