1. See for example B. A. Abeles in Applied Solid State Science, edited by R. Wolfe (Academic, New York, 1976) Vol. 6, p. 1; B. A. Abeles, H. L. Pinsh, and J. I. Gittleman, Phys. Rev. Lett. 35, 247 (1976); or C. J. Lobb, M. Tinkham, and W. J. Skocpol, Solid State Comm. 27, 1253 (1978).
2. See the excellent review by D. Stauffer, Phys. Reports 54, 1, (1979) and references therein.
3. L. P. Kadanoff et al., Rev. Mod. Phys. 39, 395 (1967).
4. S. Kirkpatrick, A.I.P. Conf. Proc. 50, 99 (1977) and A.I.P Conf. Proc. 58, 79 (1979).
5. H. E. Stanley J. Phys. A 10, L211 (1977).