1. H. Stablein, in ?Ferromagnetic Materials: A Handbook on the Properties of Magnetically Ordered Substances?, Vol. 3, edited by E. P. Wohlfarth (North-Holland, Amsterdam, 1982) Ch. 7, p. 441.
2. O. Kubo andE. Ogawa,J. Magn. Magn. Mater. 134 (1994) 376.
3. A. Morisaico, M. Matsumoto andM. Naoe,IEEE Trans. Mag. MAG-22 (1986) 1146.
4. V. V. Pankov, M. Pernet, P. Germi andP. Mollard,J. Magn. Magn. Mater. 120 (1993) 69.
5. Q. A. Pankhurst, D. H. Jones, A. H. Morrish, X. Z. Zhou andA. R. Corradi, in ?Proceedings of the International Conference on Ferrites?, Bombay, India, 10?13 January 1989, edited by C. M. Srivastava and M. J. Patni (Trans Tech Publications Ltd, Aerdermannsdorf, Switzerland, 1990) p. 323.