1. Topics in Applied Physics,1978
2. G. Alefeld: Phys. Stat. Sol. 32, 67 (1969)
3. A.S.Nowick, B.S. Berry: Anelastic Relaxation in Crystalline Solids (Academic Press, New York-London 1972)
4. H. Kanzaki: J. Phys. Chem. Solids 2, 24 (1957)
5. H. Loos: Thesis, Technische Universität, München (1976)