1. B. F. Brown: ASME Paper No. 69-MET-10,1969.
2. R. W. Nichols:Brit. Weld. J., 1968, vol. 15, pp. 21–42,75–84.
3. Book of ASTM Standards, 1969, Part 31, pp. 1099–1115.
4. W. F. Brown, Jr., and J. E. Srawley:Amer. Soc. Test. Mater., Spec. Tech. Publ. 410, 1966.
5. C.S. Carter:Eng. Fract. Mech., 1971, vol. 3, pp. 1–13.