NURKANOVIĆ, M. .; NURKANOVIĆ, Z. . Birkhoff Normal Forms, Kam Theory, Periodicity and Symmetries for Certain Rational Difference Equation With Cubic Terms. Sarajevo Journal of Mathematics, [S. l.], v. 12, n. 2, p. 217–231, 2024. DOI: 10.5644/SJM.12.2.08. Disponível em: https://sjm.anubih.ba/index.php/sjm/article/view/190. Acesso em: 15 oct. 2024.