BARKOVSKAYA, N. V. Boundedness of solutions of differential equations with delayed argument, «close» to the linear . Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 18, n. 3, p. 100–103, 1966. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8741. Acesso em: 11 apr. 2025.