1. For surveys of the modern theory of critical phenomena, including references to the original literature, see the following reviews: K. G. Wilson and J. K.gut, Physics Reports 12C, No. 2 (1974).
2. M. E. Fisher, Rev. Mod. Phys. 46, 597 (1974).
3. E. Brézin, J. C. Le Guillou, and J. Zinn-Justin, in Phase Transitions and Critical Phenomena, ed. by C. Domb and M. S. Green (Academic Press, New York, 1975 ), Vol. VI.
4. F. J. Wegner, in Trends in Elementary Particle Theory ( Springer-Verlag, Berlin, 1975 ), p. 171.
5. K. Wilson, Rev. Mod. Phys. 47, 773 (1975).