EIDELMAN, Y.; YAKUBOV, Y. Two-point boundary value problems for differential-operator equations. Збірник Праць Інституту математики НАН України, [S. l.], v. 13, n. 1, p. 58–75, 2016. Disponível em: https://trim.imath.kiev.ua/index.php/trim/article/view/207. Acesso em: 29 квіт. 2024.