1. P.J. Bray, F. Bucholtz, A.E. Geissberger and I.A. Harris, Nucl. Instr. Meth. 199 (1982)1.
2. P.C. Taylor, E.J. Friebele and M. Rubinstein,Physics of Structurally Disordered Solids, ed. S. Mitra (Plenum Press, New York, 1974) p. 665.
3. J. Szeftel and H. Alloul, J. of Non-Cryst. Solids 29(1978)253.
4. See a first review by J. Durand:Atomic Energy Review, Suppl. 1, ed. U. Gonser (IAEA, Vienna, 1981) p. 143.
5. See a review by F.E. Fujita.Atomic Energy Review, Suppl. 1 (1981) p. 173; and U. Gonser, ibid, p. 203.