1. Riccati, J.F.: Animadversiones in aequationes differentiales secundi gradus. Acta Eruditorum Lipsiae, Supplementa, VIII, II (1724) 66–73
2. Kaiman, R.E.: New methods in Wiener filtering. Proc. of First Symp. on Eng. Applications of Random Function Theory and Probability (J. Bogdanoff and F. Kozin eds.), J. Wiley 1963, 270–388
3. Kwakernaak, H; Sivan R.: Linear Optimal Control Systems. J. Wiley 1972
4. Anderson, B.D.O.; Moore, J.B.: Linear Optimal Control. Prentice Hall 1971
5. Yakubovich, VA.; Starzhinskii, V.M.: Linear Differential Equations with Periodic Coefficients. Wiley 1972