1. Theoretical Astrophysics;Ambarzumian,1958
2. Application of Invariant Imbedding to Reactor Physics;Aoki,1972
3. On the principle of invariant imbedding and propagation through inhomogeneous media;Bellman,1956
4. On the principle of invariant imbedding and neutron transport theory, I. One-dimensional case;Bellman;J. Math. Mech.,1958
5. Invariant imbedding and neutron transport theory, II. Functional equations;Bellman;J. Math. Mech.,1958