GABREL', O. M.; MULYAVKA, O. H. Approximate Solution of the de la Vallée Poussin Problem for a Differential Equation of Neutral Type by the Projection-Iterative Method. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 55, n. 2, p. 278–283, 2003. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3905. Acesso em: 7 apr. 2025.