1. I. M. Babakov, Theory of Vibrations [in Russian], Nauka, Moscow (1965).
2. P. Gashchuk and L. M. Zorii, Linear Models of Discrete Continuous Mechanical Systems [in Ukrainian], Ukrains’ki Tekhnologii, Lviv (1999).
3. F. R. Gantmakher, Matrix Theory [in Russian], Nauka, Moscow (1966).
4. S. M. Grimberg, “Calculating the frequencies of flexural-and-torsional vibrations of axial-flow compressor blades,” in: Strength Analysis [in Russian], Mashinostroenie, Moscow (1963), pp. 239–361.
5. Vibrations of Linear Mechanical Systems, Vol. 1 of the six-volume series Vibrations in Engineering [in Russian], Mashinostroenie, Moscow (1978).