1. G. MacZura, K.P. Goodboy and J.J. Koenig, in: Kirk-Othmer Encyclopaedia of Chemical Technology, ed. F. Mark, D.F. Othmer, C.G. Overberger and G.T. Seaborg, Vol. 2 (John Wiley, New York, 1978) p. 281.
2. K. Wade and A.J. Banister, in: Comprehensive Inorganic Chemistry, ed. J.C. Bailar, Jr., H.J. Emeléus, R. Nyholm and A.F. Trotman-Dickenson, Vol. 1 (Pergamon, Oxford, 1973) ch. 12, p. 993.
3. P. Swift, Surf. Intf. Anal. 4 (1982) 47.
4. M.P. Seah, in: Practical Surface Analysis, ed. D. Briggs and M.P. Seah, Vol. 1, Auger and X-ray Photoelectron Spectroscopy, 2nd Ed. (John Wiley, Chichester, 1990) p. 543.
5. C.R. Werrett, A.K. Bhattacharya and D.R. Pyke, Appl. Surf. Sci., in press.