1. D. R. Frankl, Electrical Properties of Semiconductor Surfaces, Pergamon Press, New York (1967).
2. A. Many, E. Harnik, and Y. Margoninski, in Semiconductor Surface Physics(R. H. Kingston, ed.), Univ. of Pennsylvania Press (1957), p. 85.
3. F. F. Volkenstein, The Electronic Theory of Catalysis on Semiconductors, Macmillan, New York (1953).
4. S. R. Morrison, J. Catalysis 20, 110 (1971).
5. V. J. Lee, J. Chem. Phys. 55, 2905 (1971).