1. Presnyakov, A. A., and Chervyakova, Fiz. Met. i Metallovedenie, 8, 114 (1959).
2. Underwood, E. E., Trans. Amer. Inst. Min. Met. Eng., 206, 914 (1962).
3. Backofen, W. A., Turner, I. R., and Avery, D. H., Trans. Amer. Soc. Metals, 57, 980 (1964).
4. Herring, C., J. App. Phys., 21, 437 (1950).
5. Roberts, A. C., and Cottrell, A. H., Phil. Mag., 1, 711 (1956).