1. Excellent reviews of normal tunneling are (a) C. B. Duke, Tunneling in Solids Suppl. 10, Solid State Physics (Academic Press, New York 1969).
2. E. L. Wolf, “Nonsuperconducting Electron Tunneling Spectroscopy,” in Solid State Physics, Vol. 30, Ed. by H. Ehrenreich, F. Seitz, and D. Turnbull, (Academic Press, New York 1975).
3. Good general reviews of superconducting tunneling are.
4. L. Solymar, Superconducting Tunneling and Applications (Chapman and Hall, London 1972).
5. E. L. Wolf, “Electron Tunneling Spectroscopy,” Rep. Prog. Phys. 41, 1439 (1978).