1. 1A. G. Evans, R. C. Bradt, D. P. H. Hasselman, and F. F. Lange ; pp. 17 -48, in Fracture Mechanics of Ceramics , Vol. I . Plenum, New York, 1974 .
2. 2S. M. Wiederhorn, R. C. Bradt, D. P. H. Hasselman, and F. F. Lange ; 613 -46, in Fracture Mechanics of Ceramics , Vol. 2 . Plenum, New York, 1974 .
3. 3A. G. Evans, J. J. Burke, A. E. Gorum, and R. N. Katz ; pp. 373 -96, in Ceramics for High Performance Applications . Brook Hill, Chestnut Hill, Mass., 1974 .
4. 4S. M. Wiederhom ; pp. 633 -63 in Ref. 3.