1. 1) J. Gurland and P. Bardzil: Trans. AIME, 203 (1955), 311.
2. 2) H. E. Exner and J. Gurland: Powder Metallurgy, 13 (1970), 13.
3. 3) G. S. Kreimer: Strength of Hard Alloys, Consultants Bureau, New York, (1968).
4. 4) H. Doi, Y. Fujiwara and K. Miyake: Trans. JIM, 9 (1968), 616.
5. 5) H. Doi, Y. Fujiwara and K. Miyake: Trans. Met. Soc. AIME, 245 (1969), 1457.