1. I. N. Sergeev, “Determination of complete frequencies of solutions of a linear system,” Differ. Uravn., 45, No. 6, 908 (2009).
2. I. N. Sergeev, “Comparison of complete frequencies and walk exponents of solutions of a linear system,” ibid., 46, No. 11, 1667–1668 (2010).
3. D. S. Burlakov and S. V. Tsoii, “Coincidence of the complete and the vector frequencies of solutions of a linear autonomous system,” ibid., 47, No. 11, 1662–1663 (2011).
4. E. E. Tyrtyshnikov, Matrix Analysis and Linear Algebra: Textbook [in Russian], Fizmatlit, Moscow (2007).
5. I. N. Sergeev, “Oscillation and walk characteristics of solutions of a linear differential system,” Izv. RAN. Ser. Mat., 76, No. 1, 149–172 (2012).