1. R. Shuhmann, Jr.:Trans. AIME, 1950, vol. 188, pp. 873–84.
2. A. Yazawa and M. Kameda:Tech. Reports Tohoku Univ., 1953, vol. 16,pp. 40–58.
3. S. Bog and T. Rosenqvist: Royal Norwegian Council for Scientific and Industrial Research, Report 12, 1958, pp. 1–20.
4. T. Rosenqvist and T. Hartvig: ibid, pp. 21–52.
5. M. Nagamori and M. Kameda:Trans. JIM, 1965, vol. 6, pp. 21–30.