1. Kirkaldy, J. S., von Destinon-Forstmann, J., and Brigham, R. J. Can. Met. Quart., 1,1962, 59.
2. Simpson, W. Page-Hersey Tubes Limited,Private communication.
3. Richardson, F.D., and Jeffes, J. H. E. J. Iron Steel Inst., 171,1952, 165.
4. Delorme, J., Martin, P., Rocques, C., and Bastien, Mem. Sci. Rev. Metallurg., 58, 1963, 423.