1. W. R. Cannon and T. G. Langdon, J. Mater. Sci.
18 (1983) 1.
2. S. K. Khandelwal and R. L. Cook, Amer. Ceram. Soc. Bull.
49 (1970) 522.
3. G. K. Dunsmore, J. E. Fenstermacher and F. A. Hummel, ibid.
40 (1961) 310.
4. H. Salmang, “Ceramics: physical and chemical fundamentals” (Butterworths, London, 1961) p. 329.
5. S. P. Chaudhuri, Trans. Indian Ceram. Soc.
32 (1973) 70.