Notes
*This research is sponsored by Union Miniere du Haut-Katanga, Brussels.
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2 R. Castaing, Rev. mét. 52, 669 (1955).
3 W. T. Read, Jr., and W. Shockley, Imperfections in Nearly Perfect Crystals (John Wiley and Sons, Inc., New York, 1952), p. 352.