1. For reviews, see G. W. Ludwig and H. H. Woodbury, in Solid State Physics, Vol. 13 (Academic Press, New York, 1962), p. 223, and G. Lancaster, Electron Spin Resonance in Semiconductors (Plenum Press, New York, 1967).
2. For reviews, see B. C. Cavenett, Adv. Phys.30, 475 (1981), and J. J. Davies, J. Cryst. Growth72, 317 (1985).
3. T. A. Kennedy, R. Magno, E. Glaser and M. G. Spencer, in Defects in Electron. Mater., eds. M. Stavola, S. J. Pearton and G. Davies, Mat. Res. Soc. Symp. Proc. Vol. 104 (Materials Research Society, Pittsburgh, 1988), p. 555.
4. E. A. Montie and J. C. M. Henning, J. Phys. C.21, L311 (1988).
5. For a review, see T. A. Kennedy and E. Glaser, in Physics ofDX Centers in GaAs Alloys, ed. J. C. Bourgoin, Solid State Phenomena Vol. 10 (Sci-Tech Publications, Vaduz, Liechtenstein, 1990), p. 53.