1. I. McCauley and F. Langenberg: Journal of Metals, 1965, vol. 17, no. 3, pp. 318–323.
2. O. Schaaber: Zeitschrift Metallkunde, 1952, vol. 43, pp. 251–258.
3. O. Schaaber: Radex Rundschau H 1, 1964, pp. 20–41.
4. H. Kuerth: Stahl und Eisen, 1919, vol. 39, p. 512.
5. D. A. Stanko: ibid., 1934, vol. 54, p. 1111.