SHOKOOH, S.; AFROUZI , G. A.; HADJIAN, A. On the existence of solutions of one-dimensional fourth-order equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 72, n. 11, p. 1575–1588, 2020. DOI: 10.37863/umzh.v72i11.569. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/569. Acesso em: 5 dec. 2025.