1. Houdremont, E.: Handbuch der Sonderstahlkunde, 3. verbess. Aufl., S. 644. Berlin, Göttingen, Heidelberg: Springer 1965
2. Woldman, N. E., Gibbons, R. C.: Engineering Alloys, 5th Edit., p. 1219. New York: Van Nostrand Reinhold Co. 1973
3. Selected Powder Diffraction Data for Minerals, International Centre for Diffraction Data, U.S.A., 1974, Card No. 8-98
4. Yamaguchi, S.: Fresenius Z. Anal. Chem. 155, 21 (1957)
5. Yamaguchi, S.: Fresenius Z. Anal. Chem. 184, 412 (1961); 256, 200 (1971); 261, 30 (1972)