- Aref Jeribi, Spectral Theory and Applications of Linear Operators and Block Operator Matrices, 2015, 193
- R. Hryniv, A. Shkalikov, A. Vladimirov, Differential Operators and Related Topics, 2000, 155
- Алексей Юрьевич Константинов, Aleksei Yur'evich Konstantinov, “О существенном спектре одного класса матричных дифференциальных операторов”, Функц. анализ и его прил., 36, № 3, 2002, 76
- Orif O. Ibrogimov, Heinz Langer, Matthias Langer, Christiane Tretter, “Essential spectrum of systems of singular differential equations”, ActaSci.Math., 79, № 3-4, 2013, 423
- Marie Chaussade-Beaudouin, Monique Dauge, Erwan Faou, Zohar Yosibash, “Free vibrations of axisymmetric shells: Parabolic and elliptic cases”, ASY, 104, № 1-2, 2017, 1
- Li Zhu, Huaqing Sun, Bing Xie, “On classification of singular matrix difference equations of mixed order”, Proceedings of the Royal Society of Edinburgh: Section A Mathematics, 2023, 1
- P. Kurasov, “Energy Dependent Boundary Conditions and the Few-Body Scattering Problem”, Rev. Math. Phys., 09, № 07, 1997, 853
- Aref Jeribi, Spectral Theory and Applications of Linear Operators and Block Operator Matrices, 2015, 139
- Ciprian G. Gal, Nadia J. Gal, “A spectral approach to ill-posed problems for wave equations”, Annali di Matematica, 187, № 4, 2008, 705
- D. A Zakora, “Spektral'nye svoystva operatora v zadache o kolebaniyakh smesi vyazkikh szhimaemykh zhidkostey”, Differencialʹnye uravneniâ, 59, № 4, 2023, 467