1. D. J. JOHNSON, J. Phys. D; Appl. Phys. 20 (1987) 286.
2. Idem in “Chemistry and Physics of Carbon”, Vol. 20, edited by P. A. Thrower (Dekker, New York, 1987) p. 1.
3. W. R. JONES and J. W. JOHNSON, Carbon 9 (1971) 645.
4. J. L. G. DaSILVA and D. J. JOHNSON, J. Mater. Sci. 19 (1984) 3201.
5. C. B. NG, G. W. HENDERSON, M. BUECHLER and J. L. WHITE, in Proceedings of 16th Biennial Conference on Carbon, San Diego, 1983 (American Carbon Society and University of California, San Diego, 1983) p. 515.