SHVARTSMAN, P. A. Generalization of the Lidskii theorem on the localization of the spectrum of a product of Hermitian operators. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 51, n. 7, p. 980–988, 1999. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4687. Acesso em: 5 dec. 2025.