1. Köster, W., Bangert, L., and Hahn, R., Archiv. Eisenhüttenw., 25, 569 (1954).
2. Petarra, D. P., thesis, Columbia Univ. (1962).
3. Köster, W., and Kampschulte, G., Archiv. Eisenhütten W., 32, 809 (1961).
4. Stringer, J., and Rosenfield, A. R. (unpublished results).
5. Szkopiak, Z. C., interim report (Battersea College of Technology, London, 1961).