1. See, e.g., J. G. Dash, Phase transitions at interfaces: Roughening, surface melting and triple point wetting, Solvay Conference on Surface Science (University of Texas, 1987).
2. H. J. Lauter, Inelastic neutron scattering from adsorbates, Phonons 89, S. Hunklinger, W. Ludwig, and G. Weiss, eds. (World Scientific, Singapore, 1990), p. 871.
3. M. W. Cole, Rev. Mod. Phys. 46, 451 (1974);
4. C. C. Grimes, Surf. Sci. 73, 379 (1978);
5. V. S. Edel'man, Sov. Phys. Usp. 23, 227 (1980);