1. See eg., Domb, C., Green, M.S. (eds.): Phase transitions and critical phenomena. Vol. 6. New York: Academic Press 1976
2. Dzyaloshinsky, I.E.: J. Phys. Chem. Solids4, 241 (1958); Moriya, T.: In: Magnetism. Rado, G.T., Suhl, H. (eds.). New York: Academic Press 1963
3. Keffer, F.: In: Encyclopedia of Physics. Flügge, S. (ed.). Vol. 18/2, Wijn, H.P.J. (ed.), p. 1. Berlin, Heidelberg, New York: Springer 1966
4. Levy, P.M., Fert, A.: Phys. Rev. B23, 4667 (1981)
5. Liu, L.L.: Phys. Rev. Lett.31, 459 (1973)