1. L. GUILLET, Rev. Met. 18 (1921) 681.
2. M. GOTO and G. DOGANE, Nippon Kogyo Kwai Shi 43 (1927) 931.
3. W. L. FINK and H. R. FRECHE, Trans. AIME 104 (1933) 325.
4. S. HORI, Sumitomo Kinzoku Kogyo Kenkyu Hokoku 2 (1935) 351.
5. H. ZOLLER, Schweiz. Arch. Angew. Wiss. Tech. 26 (1960) 437.