1. W. Kingery, H. Bowen andD., Uhlmann, in ?Introduction to Ceramics? 2nd edition (Wiley, New York, 1976) p. 904.
2. Y. Kim, in ?Treatise on Materials Science and Technology?, Vol. 9, edited by Franklin F. Y. Wang (Academic Press, New York, 1976) p. 51.
3. W. Kingery, H. Bowen andD. Uhlmann, in ?Introduction to Ceramics? 2nd edition (Wiley, New York, 1976) pp. 232, 506.
4. T. Nomura andT. Yamaguchi, in ?Proceedings of International Symposium of Factors in Densification and Sintering of Oxide and Non-oxide Ceramics?, Japan, 1978, p. 110.
5. R. Pampuch, in ?Ceramic Materials, an Introduction to their Properties? (Elsevier ed., PWN-Polish Scientific Publishers, Warsaw, Poland, 1976) p. 119.