References
- Campbell , A. M. 1969 . J. Phys. C , 2 : 1492 1971, Ibid., 4, 3186; 1975, Phil. Mag 31, 1191; 1978, Ibid. B, 37, 149
- Evetts , J. E. 1970 . Phys. Rev. B , 2 : 75
- Labusch , R. 1967 . Phys. Stat. Sol , 19 : 715 1969, Crystal Lattice Defects, 1, 1
- Yamafuji , K. and Irie , F. 1967 . Phys. Lett. A , 25 : 387