Bondar, A.A. and Dymarskii, Y.M. (2011) “Submanifolds of compact operators with fixed multiplicities of eigenvalues”, Ukrains’kyi Matematychnyi Zhurnal, 63(9), pp. 1179–1189. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2796 (Accessed: 5 December 2025).