1. G. Sachs,Z. Ver. Deut. Ing. 72 (1928) 734.
2. W. Boas andE. Schmid,Z. Tech. Phys. 12 (1931) 71.
3. G. I. Taylor,J. Inst. Metals 62 (1938) 307.
4. M. R. Pickus andC. H. Mathewson,ibid. 64 (1939) 237.
5. F. Wever andW. E. Schmid,Z. Metallkde 22 (1930) 133.