MUSTAFOKULOV, R. Some boundary-value problems for a class of fourth-order differential equations on a graph. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 48, n. 4, p. 476–482, 1996. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5312. Acesso em: 5 dec. 2025.