1. A. Brandt and W. Bestermann, Archiv für das Eisenhüttenwesen,9, 541 (1959).
2. P. Holler and W. Diehl, Stahl und Eisen,4, 845 (1963).
3. V. F. Korotkov, N. N. Timoshenko, and A. V. Titovets, Coll.: New Methods of Testing Metals [in Russian], Issue 31, Metallurgizdat, Moscow (1963), p. 7.
4. L. Kidman, Rev. Metallurgie,5, 569 (1964).
5. Yu. M. Buravlev, N. V. Bryanov, V. I. Ustinova, A. V. Titovets, and V. F. Korotkov, Proceedings of the All-Union Standard Specimens Research Institute [in Russian], Vol. 2, Metallurgiya, Moscow (1965), p. 114.