1. “Diffuse Reflection of Light by a Foggy Medium,”;Ambarzumian;Dokl. Akacl. Nauk SSSR,1943
2. Radiative Transfer;Chandrasekhar,1960
3. Introduction to Transport Theory;Wing,1962
4. Vistas of Modern Mathematics;Bellman,1968
5. R. Bellman and G. M. Wing. Invariant Imbedding, (to appear)