1. J. LANKFORD, L. RABENBERG and R. A. PAGE,J. Mater. Sci., in press.
2. R. P. INGEL, PhD thesis, The Catholic University of America (1982).
3. J. LANKFORD, in “Fracture Mechanics of Ceramics”, Vol. 5, edited by R. C. Bradt, A. G. Evans, D. P. H. Hasselman and F. F. Lauge (Plenum, New York, 1983) p. 625.
4. J. LANKFORD, in “Advances in Structural Ceramics”, Vol. 78, edited by P. F. Becher, M. V. Swain and S. Somiya (Materials Research Society, Boston, 1987) p. 61.
5. A. R. ROSENFIELD and B. L. AVERBACH,Acta Metall. 10 (1962) 71.