A boundary-value problem for the fourth-order equation with multiple characteristics in a rectangular domain. Neliniini Kolyvannya, [S. l.], v. 24, n. 3, p. 291–305, 2021. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/1031. Acesso em: 6 dec. 2025.