1. “On the Principle of Invariant Imbedding and Propagation Through Inhomogeneous Media”;Bellman;Proc. Natl. Acad. Sci. U.S.A.,1956
2. M. R. Scott, “A Bibliography on Invariant Imbedding and Related Topics”, Sandia Laboratories, SLA-74-0284, Albuquerque, New Mexico 87115.
3. “A New Initial-Value Method for Internal Intensities in Radiative Transfer”;Kagiwada;The Astrphys. J.,1967
4. “Invariant Imbedding and the Numerical Integration of Boundary-Value Problems for Unstable Linear Systems of Ordinary Differential Equations”;Bellman;Comm. A.C.M.,1967