1. 5) J.A. HENDRIIKSON, D.S. WOOD, and D.S. CLARK: Trans. ASM, 50 (1958), p.656
2. 6) B. COTTERELL: British Welding J., 9 (1962), p.83
3. 7) G.D. FEARNEHOUGH and C.I. HOY: JISI, 202 (1964), p.912
4. 8) J.C. RADON: JISI, 203 (1965), p.1028
5. 9) D.E.W. STONE and C.E. TURNER: Pro. Royal So. A, 285 (1965), p.83