1. I. Narisawa, “Materials Strength in Plastics” (in Japanese) (Ohm Press, Tokyo, 1982) 163.
2. Y. Higo and S. Nunomura, in Proceedings of 2nd Symposium on Non-destructive Evaluation in New Materials and Products, Tokyo (1988) 131.
3. Y. Hushimi and A. Wada, Rev. Sci. Instrum.
47(2) (1976) 213.
4. H. Kawabe and Y. Higo, J. Mater. Sci.
27 (1992) 5547.
5. Idem, in “Nondestructive Characterization of Material V, Tokyo (1992) 745.