1. Koehler, W. C. and Wollan, E. O., Phys. Rev., 97, 1177 (1955).
2. In many cases the same crystals were investigated at the two laboratories due to the courtesy of Dr. F. H. Spedding.
3. See, for example, Bozorth, R. M. and Graham, Jr., C. D., in Rare Earth Metals, Compounds, and Solid Solutions, Handbook of Magnetic Materials and Their Properties (P. Albert and F. Luborski, eds.). Reinhold Press (1970)
4. and Tebble, R. S. and Craik, D. J., in Magnetic Materials. Wiley-Interscience (1969). See especially Chapter 6.
5. Koehler, W. C., J. Appl. Phys., 36, 1078 (1965)