1. M. F. Ashby, Acta Met. 20 (1972) 887.
2. A. G. Guy, ?Essentials of Materials Science? (McGraw-Hill, New York, 1976) p. 324.
3. R. W. Hertzberg, ?Deformation and Fracture Mechanics of Engineering Materials? (John Wiley, New York, 1976) p. 156.
4. W. D. Kingery, H. K. Bowen and D. R. Uhlmann, ?Introduction to Ceramics,? 2nd edition (John Wiley, New York, 1976) p. 745.
5. B. Ilschner, ?Hochtemperatur-Plastizität?, Reine und angewandte Metallkunde in Einzeldarstallungen, Vol. 23 (Springer-Verlag, Berlin, 1973) p. 258.