1. Astiz, M.A., Elices, M., and Galvez, V.S. (1975) Proc. ICF4, Waterloo, Canada 3, 395.
2. Blackburn, W.S. (1972) Int. J. Fracture 8, 343.
3. Budianski, B., and Rice, J.R. (1973) J. Appl. Mech. 40, 201.
4. Knowles, J.K., and Sternberg, E. (1972) Archive for Rat. Mech. Anal. 44, 187.
5. Kubo, S. (1975) Study on Mechanics of Crack Initiation and Growth, Osaka University Doctoral Thesis (in Japanese)