NIZHNIK, L. P. Stable difference scheme for a nonlinear Klein-Gordon equation. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 6, p. 857–859, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5073. Acesso em: 14 apr. 2025.