Rafa Espínola, Miguel Lacruz, “Applications of fixed point theorems in the theory of invariant subspaces”, Fixed Point Theory Appl, 2012, № 1, 2012, 197
Sergio Albeverio, Alexander K. Motovilov, “Sharpening the Norm Bound in the Subspace Perturbation Theory”, Complex Anal. Oper. Theory, 7, № 4, 2013, 1389
David Krejčiřík, Petr Siegl, Jakub Železný, “On the Similarity of Sturm–Liouville Operators with Non-Hermitian Boundary Conditions to Self-Adjoint and Normal Operators”, Complex Anal. Oper. Theory, 8, № 1, 2014, 255
S. Albeverio, A. K. Motovilov, “Solvability of the Operator Riccati Equation in the Feshbach Case”, Math Notes, 105, № 3-4, 2019, 485
James Adduci, Boris Mityagin, “Eigensystem of an L 2-perturbed harmonic oscillator is an unconditional basis”, centr.eur.j.math., 10, № 2, 2012, 569
Stephen Sorokanich, “Beyond mean-field: Condensate coupled with pair excitations”, Journal of Mathematical Physics, 64, № 8, 2023, 081904
Jussi Behrndt, Friedrich Philipp, Carsten Trunk, “Bounds on the non-real spectrum of differential operators with indefinite weights”, Math. Ann., 357, № 1, 2013, 185
S. Albeverio, A. K. Motovilov, “On invariant graph subspaces of a J-self-adjoint operator in the Feshbach case”, Math Notes, 100, № 5-6, 2016, 761
Bogdan D. Djordjević, “On a Singular Sylvester Equation with Unbounded Self-Adjoint A and B”, Complex Anal. Oper. Theory, 14, № 4, 2020, 43
Manoussos Grillakis, Dionisios Margetis, Stephen Sorokanich, “Many-body excitations in trapped Bose gas: A non-Hermitian approach”, Quart. Appl. Math., 81, № 1, 2022, 87