MOGILEVSKII, V. I. Boundary triplets and Titchmarsh-Weyl functions of differential operators with arbitrary deficiency indices. Methods of Functional Analysis and Topology, [S. l.], v. 15, n. 3, p. 280–300, 2009. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/425. Acesso em: 18 dec. 2025.