1. 4) J. H. WESTBROOK: I. Metals, 209 (1957), p.898
2. 6) F. B. FOLEY and V. N. KRIVIBOK: Metal Progress, 71 (1957) May, p.81
3. 7) V. V. LEVITIN: Phys. Met.& Metallog., 11 (1961), p.67
4. 8) K. BUNGARDT and G. LENNARTZ: Arch. Eisenhüttenw., 34 (1963), p.531
5. 9) C. CRUSSARD, J. PLATEAU and G. HENRY: Joint International Conference on Creep, 1 (1963), p.91