1. T. Ya. Azizov and I. S. Iokhvidov,Fundamentals of the Theory of Linear Operators in Spaces with Indefinite Metric [in Russian], Nauka, Moscow (1986).
2. A. I. Mal'tsev,Fundamentals of Linear Algebra, [in Russian], Gostekhizdat, Moscow-Leningrad (1948).
3. I. Gohberg, P. Lancaster, and L. Rodman,Matrices and Indefinite Scalar Products, Birkhäuser, Basel (1983).
4. A. A. Shkalikov, “Operator pencils arising in elasticity and hydrodynamics: the instability index formula,” in:Operator Theory: Advances and Applications, Vol. 87, Birkhäuser, Basel (1996), pp. 258–285.
5. T. Ya. Azizov and L. I. Sukhocheva, “A new approach to the proof of the theorem on the reduction of matrices to the Jordan normal form,” in:Functional Analysis. Linear Spaces [in Russian], Ulyanovsk (1990), pp. 3–5.