1. M. R. Scott, Invariant Imbedding and its Applications to Ordinary Differential Equations, Addison-Wesley, Reading, Mass., 1973.
2. J. L. Casti and R. E. Kalaba, Imbedding Methods in Applied Mathematics, Addison-Wesley, Reading, Mass., 1973.
3. R. E. Bellman and G. M. Wing, An Introduction to Invariant Imbedding, John Wiley and Sons, New York, 1975.
4. D. O. Banks and G. J. Kurowski, Computations of Eigenvalues of Singular Sturm-Liouville Systems, Math. Comput. 22: 304–310 (1968).
5. I. T. Elder, An Invariant Imbedding Method for Computation of Eigenlengths of Singular Two-Point Boundary-Value Problems, J. Math. Anal. Appl., to appear.