1. J.D. Gunton, M.S. Miguel, and P.S. Sahni, in Phase Transitions and Critical Phenomena, Vol. 8, eds. C. Domb and J.L. Lebowitz (Academic Press, New York, 1983).
2. K. Binder, Rep. Prog. Phys. 50 (1987) 783.
3. For recent reviews, see, e.g., Dynamics of First Order Phase Transitions, eds. H. J. Herrmann, W. Janke, and F. Karseh (World Scientific, Singapore, 1992).
4. B.A. Berg and T. Neuhaus, Phys. Lett. B267 (1991) 249.
5. For earlier related ideas, see G.M. Torrie and J.P. Valleau, Chem. Phys. Lett. 28 (1974) 578.