NITZ, O. Generalized resolvents of isometric linear relations in Pontryagin spaces, II: Krein-Langer formula. Methods of Functional Analysis and Topology, [S. l.], v. 6, n. 3, p. 72–96, 2000. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/126. Acesso em: 17 dec. 2025.