1. E. M. Lifshitz andL. P. Pitaevskii:Statistical Physics, Part 1, p. 529.
2. E. Brézin, B. I. Halperin andS. Leibler:J. Phys.,44, 775 (1983).
3. R. Lipowsky:Phys. Rev. B,32, 1731 (1985).
4. Actually,A=12πH is usually called the Hamaker constant. SeeJ. N. Israelachvili:Intermolecular and Surface Forces (Academic Press, San Diego, Cal., 1985).
5. For a review of recent experiments, seeJ. G. Dash:Contemp. Phys.,30, 6961 (1988);J. G. Dash: inSolvay Conference on Surface Science, edited byF. W. de Wette (Springer-Verlag, Berlin, 1988), p. 142.