AZIZOV, T. Ya.; STRAUSS, V. A. On a spectral decomposition of a commutative operator family in spaces with indefinite metric. Methods of Functional Analysis and Topology, [S. l.], v. 11, n. 1, p. 10–20, 2005. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/262. Acesso em: 16 dec. 2025.