1. A. Van Wieringen and N. Warmoltz, Physica 22:849 (1956).
2. S.T. Picraux and F.L. Vook, Phys. Rev. B14:1593 (1976).
3. S.T. Picraux and F.L. Vook, Phys. Rev. B18:2066 (1978).
4. S.T. Picraux, F.L. Vook, and H.J. Stein in: “Defects and Radiation Effects in Semiconductors, 1978,” ed. J.H. Albany (Inst. Phys. Bristol, 1979) p. 31.
5. J.A. Appelbaum, D.R. Hamann, and K.H. Tasso, Phys. Rev. Lett. 38:1478 (1977).