1. R. E. Kalman, in Proceeding of the First International Conference of the IFAC, Moscow, Russia, 1960 (Izd. Akad. Nauk SSSR, Moscow, 1961), Vol. 2, pp. 521–546.
2. E. L. Yip and R. F. Sincovec, IEEE Trans. Autom. Control. 26, 702–707 (1981).
3. A. Ailon, Trans. Automat. Control 32(5), 429–432 (1987).
4. S. P. Zubova, Autom. Remote Control 72(1), 23–37.