1. Y. Tanabe and S. Sugano, J. Phys. Soc. Japan 9, 766 (1954).JUPSAU0031-9015
2. E. U. Condon and G. H. Shortley, The Theory of Atomic Spectra (Cambridge University Press, Cambridge, England, 1959).
3. D. Seed, M.Sc. thesis, University of Canterbury, New Zealand, 1961.
4. J. S. Griffith, The Theory of Transition Metal Ions (Cambridge University Press, Cambridge, England, 1961).
5. U. Fano and G. Racah, Irreducible Tensorial Sets (Academic Press Inc., New York, 1959).