1. V. R. Vogel and H. Baur:Arch. Eisenhuettenw., 1933, vol. 6, pp. 495–500.
2. V. O. Meyer and F. Schulte:Arch. Eisenhuettenw., 1934, vol. 8, pp. 187–95.
3. V. F. Körber and W. Oelsen: unpublished research quoted in Ref. 4, p. 441.
4. V. F. Körber:Stahl Eisen, 1936, vol. 56, pp. 433–44.
5. W. Wentrup:Tech. Mitt. Krupp, 1937, vol. 5, pp. 131–52.