1. A. Jung, Kunstoffe 63 (1973) 802.
2. D. Bürkle ibid 65 (1975) 25.
3. R. So and L. J. Broutman, International Conference on Deformation and Fracture, Churchill College, Cambridge, (1976), (Plastics and Rubber Institute, London, 1976).
4. H. Höberg, Kunstoffe 47 (1957) 371.
5. R. G. Treuting and W. T. Read, J. Appl. Phys. 22 (1951) 130.