1. The method of calculations is described in the following reference books; Samuel Glasstone,Principles of Nuclear Reactor Engineering(Princeton University Press, Princeton, 1955);
2. Raymond L. Murray,Introduction to Nuclear Engineering(New York, 1954);
3. Richard Stephenson,Introduction to Nuclear Engineering(New York, 1954).
4. F. W. Clarke,The Data of Geochemistry(Washington, 1924).