ATEIWI, A. M. On the problem on periodic solutions of one class of systems of difference equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 2, p. 309–314, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5008. Acesso em: 14 apr. 2025.