1. G. R.Irwin Structural Mechanics, Pergamon Press, 557 (1960).
2. H.H.Johnson and A.M.Willner Appl. Matls. Res., 34 (January 1965).
3. G. G. Hancock and H. H. Johnson Trans. RIME, 236, 513 (1966)
4. G. L. Hanna, A. R.Troiano and E. A.Steigerwald, Trans. ASM, 57, 658 (1964).
5. G.L. Hanna and E. A. Steigerwald “Influence of Environment on Crack Propagation and Delayed Failures in High Strength Steels,” Tech.Doc.Rept. No. RTD-TDR-63-4225, Air Force Materials Laboratory (January 1964).