1. P. L. Murray, D. Livey and J. Williams, ?Ceramic Fabrication Process? (Wiley, New York, 1958) p. 147.
2. R. L. Coble, J. Appl. Phys. 41 (12) (1970) 4798.
3. H. K. Palmer and R. C. Rowe, Powder Technol. 10 (1974) 225.
4. H. Sekito and H. Kuno, J. Jap. Soc. Powder Met. to be published.
5. I. J. Bear and V. Barday, Powder Met. Int. 7 (3) (1975) 121.