1. D. Marshall, A. G. Evans andM. Drory, Transformation Toughening in Ceramics, in ?Fracture Mechanics of Ceramics?, Vol. 6, edited by R. C. Bradt, A. G. Evans, D. P. H. Hasselman and F. F. Lange (Plenum, New York, 1983) pp. 289?307.
2. A. G. Evans, Toughening Mechanisms in Zirconia Alloys, in ?Fracture in Ceramics Materials?, edited by A. G. Evans (Noyes, New Jersey, 1984) pp. 15?55.
3. C. A. Anderson andT. K. Gupta, Phase Stability and Transformation Toughening in Zirconia, in ?Science and Technology of Zirconia, Advances in Ceramics?, Vol. 3, edited by A. H. Heuer and L. W. Hobbs (American Ceramic Society, Ohio, 1981) pp. 184?201.
4. P. F. Becher, M. V. Swain andM. K. Ferber,J. Mater. Sci. 22 (1987) 76.
5. N. Claussen andM. R�hle, Design of Transformation Toughened Ceramics, in ?Science and Technology of Zirconia, Advances in Ceramics?, Vol. 3, edited by A. H. Heuer and L. W. Hobbs (American Ceramics Society, Ohio, 1981) pp. 137?63.