- Heinz Langer, Christiane Tretter, Operator Theory and Analysis, 2001, 331

- S. Albeverio, A. K. Motovilov, “Solvability of the Operator Riccati Equation in the Feshbach Case”, Math Notes, 105, № 3-4, 2019, 485

- Алексей Юрьевич Константинов, Aleksei Yur'evich Konstantinov, “Спектральный анализ одного класса матричных дифференциальных операторов”, Функц. анализ и его прил., 31, № 3, 1997, 77

- A. K. Motovilov, “Alternative proof of the a priori tan Θ theorem”, Theor Math Phys, 186, № 1, 2016, 83

- A. K. Motovilov, R. Mennicken, Mathematical Results in Quantum Mechanics, 1999, 315

- R. Mennicken, A. K. Motovilov, Operator Theory and Related Topics, 2000, 287

- 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

- A. A. Shkalikov, “Dissipative operators in the Krein space. Invariant subspaces and properties of restrictions”, Funct Anal Its Appl, 41, № 2, 2007, 154

- D. A Zakora, “Spektral'nye svoystva operatora v zadache o kolebaniyakh smesi vyazkikh szhimaemykh zhidkostey”, Differencialʹnye uravneniâ, 59, № 4, 2023, 467

- B. S. Pavlov, “Krein formula with compensated singularities for the ND-mapping and the generalized Kirchhoff condition at the Neumann Schrödinger junction”, Russ. J. Math. Phys., 15, № 3, 2008, 364
