1. G. D. Miles, R. A. J. Sambell, J. Rutherford, and G. W. Stephenson, Trans. Brit. Ceram. Soc. 66 (1967) No. 7, 319.
2. H. G. Tattersall and G. Tappin, J. Mater. Sci. 1 (1966) 296.
3. R. W. Davidge and G. Tappin, ibid 3 (1968) 765.
4. Idem, Trans. Brit. Ceram. Soc. 66 (1967) No. 8, 405.
5. W. N. Reynolds, 1970, Society of Chemical Industry, 3rd. Conf. on Industrial Carbons and Graphite.