1. Excellent summaries of the current status of most of these techniques can be found in the proceedings of three International Conferences on the Structure of Surfaces:
2. The Structure of Surfaces (M. A. Van Hove and S. Y. Tong, eds.), Springer Verlag, Berlin (1985);
3. The Structure of Surfaces II (J. F. van der Veen and M. A. van Hove, eds.), Springer-Verlag, Berlin (1988);
4. The Structure of Surfaces III (S. Y. Tong, M. A. Van Hove, K. Takayanagi, and X. D. Xie, eds.), Springer-Verlag, Berlin (1991).
5. K. Siegbahn, U. Gelius, H. Siegbahn, and E. Olsen, Phys. Lett. 32A, 221 (1970).