1. Chandrasekhar, S.: Radiative Transfer. New York: Dover Publications, Inc. 1960.
2. Agranovich, Z. S. andV. A. Marchenko: The Inverse Problem of Scattering Theory. New York: Gordon and Breach, 1963.
3. Bellman, R. E., H. H. Kagiwada, R. E. Kalaba, andSueo Ueno: On the Identification of Systems and the Unscrambling of Data. — II: An Inverse Problem in Radiative Transfer. The RAND Corporation, RM-4332-ARPA. September 1964.
4. Bellman, R. E.: Dynamic Programming. Princeton, New Jersey: Princeton University Press, 1957.
5. Bellman, R. E. andR. E. Kalaba: “Transport Theory and Invariant Imbedding.” Nuclear Reactor Theory, pp. 206–218, edited by G. Birkhoff and E. Wigner. Providence, Rhode Island: American Mathematical Society, 1961.