1. S. GLASSTONE AND M. C. EDLUND, “The Elements of Nuclear Reactor Theory,” Chapter V, pp. 90–189 van Nostrand, Princeton, New Jersey, 1952.
2. A Numerical Technique for Solving Group Diffusion Equations
3. E. L. WACHSPRESS, TWO point boundary value problem, Chapter 10 in “Numerical Methods for Digital Computers,” edited by A. Ralston and H. S. Wilf. Wiley, New York, 1960.