1. 1) F. W. Wiffen: Defects and Defect Clusters in B.C.C. Metals and their Alloys, NBS, (1973), p. 176.
2. 2) H. Conrad: Mechanical Bevavior of Metals at Elevated Temperatures, McGraw-Hill, (1961), p. 185.
3. 3) R. J. Arsenault: Acta Met., 15 (1967), 1853.
4. 4) D. F. Hasson, Y. Huang, E. Pink and R. J. Arsenault: Met. Trans., 5 (1974), 371.
5. 5) P. Groh, F. Vanoni and P. Moser: Defects and Defect Clusters in B.C.C. Metals and their Alloys, NBS, (1973), p. 19.