Sufficient conditions for existence of bounded solutions for systems of nonlinear difference equations. Neliniini Kolyvannya, [S. l.], v. 8, n. 2, p. 165–173, 2005. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/344. Acesso em: 22 jan. 2026.