1. Wegner, F.J.: Phys. Rev. B19, 783 (1979)
2. Langer, J.S., Neal, T.: Phys. Rev. Lett.16, 984 (1966)
3. Brézin, E., Le Guillou, J.C., Zinn-Justin, J.: Domb, C., Green, M.S.: Phase Transitions and Critical Phenomena, Vol. 6, London, New York: Academic Press 1976
4. Bronk, B.V.: J. Math. Phys.5, 215 (1964)
5. Metha, M.L.: Random Matrices and the Statistical Theory of Energy Levels, London, New York: Academic Press 1967