1. 1) A. S. Nowick: Progress in Metal Physics, 4 (1953).
2. 2) A. S. Nowick and B. B. Berry: Anelastic Relaxation in Crystalline Solids, Academic Press, (1972), p. 16.
3. 3) C. Zener: Elasticity and Anelasticity of Metals, Uni. Chicago Press, (1948), p. 61.
4. 4) F. L. Vogel, Jr.: Resonance and Relaxation in Metals, Prenum Press, (1964), p. 2.
5. 5) E. Volterra: J. Appl. Mechanics, 18 (1951), 273.