1. Sommerfeld, “Atombau,” 4th Ed., p. 639.
2. Bose,Z. Physik, 1927,43, 864.
3. Stoner,Phil. Mag., 1929,8, 250.
4. Van Vleck, “Theory of Electric and Magactic Susceptibilities,” Oxford, particularly Chapter X, 73.
5. Manchot and Gall,Ber., 1928,61B, 1135,; 1927,60B, 191.