1. Bacon, R., Phil. Trans. Royal Soc. London, Ser. A, 294, p. 437, 1980.
2. Johnson, J. W., J. Appl. Poly. Sci., Symposia, 9, p. 229, 1969.
3. Johnson, J. W. and Thorne, D. J., Carbon, 7, p. 659, 1969.
4. Johnson, J. W., Rose, P. G. etal, 3rd Conf. on Ind. Carbon and Graphite, Soc. Chem. Ind., London, p. 443, 1970.
5. Whitney, W. and Kimmel, R. M., Nature Phys. Sci., 237, p. 93, 1972.