Stydying pair systems of nonlinear functional fifferential equations with restrictions. Neliniini Kolyvannya, [S. l.], v. 11, n. 2, p. 252–260, 2008. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/477. Acesso em: 21 jan. 2026.