FEDORCHUK, V. M. Symmetry reduction and some exact solutions of a nonlinear five-dimensional wave equation. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 48, n. 4, p. 573–576, 1996. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5324. Acesso em: 5 dec. 2025.