MOGILEVSKII, V. I. Boundary triplets and Krein type resolvent formula for symmetric operators with unequal defect numbers. Methods of Functional Analysis and Topology, [S. l.], v. 12, n. 3, p. 258–280, 2006. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/319. Acesso em: 16 dec. 2025.