1. F. Erdogan and G. C. Sih:J. Basic Eng., 1963, vol. 85, p. 519.
2. W. W. Gerberich and K. A. Peterson: inMicro and Macro Mechanics of Crack Growth, K. Sadananda, B. B. Rath, and D. J. Michel, eds., TMS-AIME, Warrendale, PA, 1982, p. 1.
3. J. Lankford and D. L. Davidson: inAdvances in Fracture Research, D. Francois, ed., Pergamon Press, Oxford, 1981, vol. 4, p. 899.
4. S. Suresh:Scripta Met., 1982, vol. 16, p. 995.
5. A. K. Vasudevan, P. E. Bretz, A. C. Miller, and S. Suresh:Mat. Sci. Eng., 1983, in press.