1. M. E. Fister, inCritical Phenomena, M. S. Green, ed. (Academic Press, New York, 1971).
2. M. E. Fister and M. N. Barber,Phys. Rev. Lett. 28:1516 (1972).
3. T. H. Berlin and M. Kac,Phys. Rev. 86:821 (1952).
4. H. W. Lewis and G. H. Wannier,Phys. Rev. 88:682 (1952).
5. G. S. Joyce, inPhase Transitions and Critical Pehnamena, Vol. 2, C. Domb and M. S. Green, eds. (Academic Press, New York, 1972).