ShvartsmanP. A. “Generalization of the Lidskii Theorem on the Localization of the Spectrum of a Product of Hermitian Operators”. Ukrains’kyi Matematychnyi Zhurnal 51, no. 7 (July 25, 1999): 980–988. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4687.