1. A.I. Akhiezer, V.G. Bar’yakhtar and S.V. Peletminskii, Spin Waves, North Holland, Amsterdam, 1968
2. N.W. Ashcroft and N.D. Mermin, Solid State Physics, Holt, Rinehart and Winston, New York, 1976
3. R. Becker u. W. Döring, Ferromagnetismus, Springer, Berlin, 1939
4. W.F. Brown, Magnetostatic Principles in Ferromagnetism, North Holland, Amsterdam, 1962
5. Encyclopedia of Physics;F Keffer,1966