1. J. B. Pendry, Low Energy Electron Diffraction (Academic, New York, 1974).
2. F. Jona, Discuss. Faraday Soc. 60, 210 (1975).
3. T. C. Ngoc, M. G. Lagally, and M. B. Webb, Surf. Sci. 35, 117 (1973).SUSCAS0039-6028
4. For example, Ni(100), (220), (111): J. E. Demuth, P. M. Marcus, and D. W. Jepsen, Phys. Rev. B 11, 1460 (1975); PLRBAQ0556-2805
5. Ag(111): M. G. Lagally, T. C. Ngoc, and M. B. Webb, Phys. Rev. Lett. 26, 1557 (1971).PRLTAO0031-9007