BARANETSKIJ, Ya. O.; KALENYUK, P. I.; KOLYASA, L. I. Spectral properties of nonself-adjoint nonlocal boundary-value problems for the operator of differentiation of even order. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 70, n. 6, p. 739–751, 2018. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1592. Acesso em: 27 apr. 2025.