1. Witsenhausen, H.S., Sets of Possible States of Linear Systems Given Perturbed Observations, IEEE Trans. Automat. Control, 1968, vol. AC-13, pp. 556–558.
2. Schweppe, F.C., Uncertain Dynamic Systems, Englewood Cliffs: Prentice Hall, 1973.
3. Krasovskii, N.N., On the Theory of Controllability and Observability of Linear Dynamical Systems, Prikl. Mat. Mekh., 1964, vol. 28, no. 1, pp. 3–14.
4. Kurzhanskii, A.B., Differential Observation Games, Dokl. Akad. Nauk SSSR, 1972, vol. 207, no. 3, pp. 527–530.
5. Kurzhanskii, A.B., Upravlenie i nablyudenie v usloviyakh neopredelennosti (Control and Observation under Uncertainty), Moscow: Nauka, 1977.