1. O. A. Kaibyshev, ?Superplasticity of Alloys, Intermetallics and Ceramics? (Springer Verlag, Berlin. 1992) p. 264
2. I. I. Novikov andV. K. Portnoy, ?Superplasticity of ultrafme-grained alloys? (Metallurgia, Moscow. 1981) p. 167 in Russian.
3. C. H. Hamilton, A. K. Ghosh andI. A. Wert,Met. Forum 4 (1985) 172.
4. O. A. Kaibyshev andR. Z. Valiev, ?Grain boundaries and properties of metals? (Metallurgia, Moscow, 1987) p. 214 in Russian.
5. D. S. McDarmaid, P. G. Partridge andA. Wisbey, in ?Superlasticity in Advanced Materials?, edited by S. Hori, M. Tokizana and N. Furushiro (Jap. Soc. Res. Superplast., Osaka, Japan, 1991) p. 621.