1. S. K. Bhattacharya andN. Brown,J. Mater. Sci. 19 (1984) 2519.
2. Idem, ibid. 20 (1985) 2767.
3. Idem, ibid. 20 (1985) 4553.
4. J. K. Knott, ?Fundamentals of Fracture Mechanics? (Butterworths, London, 1973) Ch. 3.
5. P. C. Paris andC. G. Sih, ASTM Technical Publication No. 381 (American Society for Testing and Materials, Philadelphia, 1965) p. 30.