1. J. P. Hirth and J. Lothe: Theory of Dislocations( McGraw-Hill, New York 1968 ) p. 353.
2. H. Gottschalk, G. Patzer, and H. Alexander: Phys. Stat. Sol. (a) 45(1978) 207.
3. A. M. Gomez and P. B. Hirsch: Phil. Mag. A38(1978) 733.
4. M. Sato, K. Hiraga, and K. Sumino: unpublished work.
5. M. Tanaka and B. Jouffrey: Phil. Mag. A50(1984) 733.