- Volker Hardt, Alexei Konstantinov, Reinhard Mennicken, “On the Spectrum of the Product of Closed Operators”, Math. Nachr., 215, no. 1, 2000, 91
- Boulbeba Abdelmoumen, Alaeddine Damergi, Yousra Krichene, “On a Riesz basis of diagonally generalized subordinate operator matrices and application to a Gribov operator matrix in Bargmann space”, Filomat, 37, no. 14, 2023, 4481
- Aref Jeribi, Spectral Theory and Applications of Linear Operators and Block Operator Matrices, 2015, 375
- D. A. Zakora, “Spectral Properties of the Operator in the Problem of Oscillations in a Mixture of Viscous Compressible Fluids”, Diff Equat, 59, no. 4, 2023, 473
- B. M. Brown, G. Grubb, I. G. Wood, “M ‐functions for closed extensions of adjoint pairs of operators with applications to elliptic boundary problems”, Mathematische Nachrichten, 282, no. 3, 2009, 314
- Reinhard Mennicken, Manfred Möller, 192, Non-Self-Adjoint Boundary Eigenvalue Problems, 2003, 101
- Aymen Ammar, Toka Diagana, Aref Jeribi, “Perturbations of Fredholm linear relations in Banach spaces with application to <mml:math altimg="si1.gif" display="inline" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd" xmlns:sa="http://www.elsevier.com/xml/common/struct-aff/dtd"><mml:mn>3</mml:mn><mml:mo>×</mml:mo><mml:mn>3</mml:mn></mml:math>-block matrices of linear relations”, Arab Journal of Mathematical Sciences, 22, no. 1, 2016, 59
- J. Lutgen, “On essential spectra of operator-matrices and their Feshbach maps”, Journal of Mathematical Analysis and Applications, 289, no. 2, 2004, 419
- Marco Marletta, Christiane Tretter, “Essential spectra of coupled systems of differential equations and applications in hydrodynamics”, Journal of Differential Equations, 243, no. 1, 2007, 36
- Nedra Moalla, “A Characterization of Schechter's Essential Spectrum by Mean of Measure of Non-Strict-Singularity and Application to Matrix Operator”, Acta Mathematica Scientia, 32, no. 6, 2012, 2329