1. H. Fritzsche, in Fundamental Physics of Amorphous Semiconductors, ed. F. Yonezawa, (Springer-Verlag, New York, 1981) p. 1.
2. G. Etherington, A. C. Wright, J. T. Wenzel, J. C. Dore, J. H. Clark and R. N. Sinclair, J. Non-cryst. Solids, 48, 265 (1982).
3. R. J. Tempkin, W. Paul and G.A.N. Connell, Adv. Phys. 22, 531 (1973).
4. R. Fainchtein, J. S. Lannin and D.L. Price, Phys. Rev. (in press).
5. D. Beeman (private communication).