1. Beck, P.A.: In: Problems in Materials Science, New York: Pergamon Press, to appear in 1978
2. Mydosh, J.A.: J.M.M.M.7, 237 (1978); and references therein
3. Anderson, P.W.: Amorphous Magnetism II, pp. 1?17. New York: Plenum Press 1977 Binder, K.: Festkörperprobleme (Advances in Solid State Physics) XVII, pp. 55?85, Braunschweig: Vieweg 1977 Heber, G.: Appl. Phys.10, 101 (1976)
4. Canella, V., Mydosh, J.A., Budnick, J.I.: J. Appl. Phys.42, 1689 (1971) Cannella, V., Mydosh, J.A.: Phys. Rev. B6, 4220 (1972)
5. de Rozario, F.A., Smith, D.A.: J. Phys. F7, 439 (1977)