1. C. R. Aita, J. Vac. Sci. Technol. A 3 (1985) 625.
2. J. W. Coburn, Thin Solid Films 171 (1989) 65.
3. G. D. Patterson, in: Treatise on Analytical Chemistry (I. M. Kolthoff, P. J. Elving, and E. B. Sandell, eds.), Vol. 10, Wiley-Interscience, New York, 1972.
4. VG 9000, VG MicroTrace, Cheshire, UK. VG Glow Quad, UK. TS SOLA, Turner Scientific, JEOL, Kratos.
5. F. W. Aston, Isotopes, 2nd ed., Longmans, Green, New York, 1924.