PELYUKH, G. P. On the existence and properties of periodic solutions of discrete difference equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 10, p. 1382–1387, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5617. Acesso em: 5 dec. 2025.