[1] Birkhoff G., McLane S.: A Survey of Modern Algebra. McMillan, New Yoгk 1965.

[2] Hautus M. L. J.: Stabilization, Controllability and Observability of Linear Autonomous Systems. Nederl. Akad. Wetensch. Proc. Ser. A73 (1970), 448-455. MR 0289170 | Zbl 0212.47302

[3] Kučera V.: A Contribution to Matrix Quadratic Equations. IEEE Trans. on Automatic Contгol AC-17 (June 1972), 344-347. MR 0449830

[4] Kučera V.: On Nonnegative Definite Solutions to Matrix Quadratic Equations. In: Proc. 5th IFAC World Congress, Vol. 4, Paris, 1972. Also to appear in Journal Automatica, July 1972. MR 0332827

[5] Kučera V.: State Space Approach to Discrete Lineaг Control. Kybernetika 8 (1972), 3, 233-251. MR 0337399

[6] Mårtensson K.: On the Matrix Riccati Equation. Infoгmation Sciences 3, (1971), 1, 17-49. MR 0280512

[7] Potteг J. E.: Matrix Quadratic Solutions. SIAM J. on Appl. Math. 14 (1966), 3, 496-501. MR 0201457

[8] Sage A. P.: Optimum Systems Control. Prentice-Hall, Englewood Cliffs, N. J. 1968. MR 0255264 | Zbl 0192.51502

[9] Wonham W. M.: On a Matrix Riccati Equation of Stochastic Control. SIAM J. on Control 6 (1968), 4, 681-698. MR 0239161

[10] Zadeh L. A., Desoer C. A.: Linear System Theory: The state Space Appгoach. McGгaw-Hill, New York 1963.