1. J. Jensen and A. R. Mackintosh, Rare Earth Magnetism: Structures and Excitations, (Clarendon Press, Oxford, 1991), International Series of Monographs on Physics, Vol. 81.
2. J. Kondo, in Solid State Physics, ed. F. Seitz, H. Ehrenreich and D. Turnbull, (Academic, New York, 1969), Vol. 23, p. 184.
3. K. G. Wilson, Rev. Mod. Phys. 47, 773 (1975).
4. P. B. Wiegmann im Quantum Theory of Solids, (Mir, Moscow, 1982), p. 238.
5. N. Andrei, K. Furuya, and J. H. Lowenstein, Rev. Mod. Phys. 55, 331, (1983)