On boundedness of solutions of a two-parameter nonlinear Volterra system. Neliniini Kolyvannya, [S. l.], v. 13, n. 4, p. 497–500, 2010. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/578. Acesso em: 21 jan. 2026.