1. J. N. Greenwood, D. R. Miller, and J. W. Suiter:ActaMet., 1954, vol. 2, p. 250.
2. A.H. Cottrell:Fracture, B. Averbachet ai, eds., p. 20, Wiley and Technology Press, New York, 1959.
3. R.C. Gifkins:Acta Met., 1956, vol. 4, p. 98.
4. E.S. Machlin:AIME Trans., 1956, vol. 206, p. 106.
5. C. W. Chen and E. S. Machlin:Acta Met., 1956, vol. 4, p. 655.