1. P.D.Townsend: In Sputtering by Particle Bombardment II, ed.R.Behrish (Springer-Verlag, Berlin, Heidelberg 1983) p.147.
2. M.Szymonski, J.Rutkowski, A.Poradzisz, Z.Postawa and B.Jorgensen: In DIET II, Springer Series in Surface Science 4 (Springer-Verlag, Berlin, Heidelberg 1984) p.160.
3. P.D.Townsend, R.Browning, D.J.Garland, J.C.Kelly, A.Mahjoobi, A.J.Michael and M.Saidoh, Rad.Effects 30, 55(1976).
4. H.Overeijnder, M.Szymonski, A.Haring and A.E.de Vries, Rad.Effects 36, 63(1978).
5. M.Szymonski, P.Czuba, T.Dohnalik, L.Jozefowski, A.Karawajczyk, J.Kolodziej, R.Lesniak and Z.Postawa, Nucl.Instrum.Methods, in press.