1. G.F. Taylor: «Apparatus for Making Hard Metal Compositions», United States Patent No. 1896854 (February 7, 1933).
2. F.V. Lenel: J. Metals, 7 (1955) 158-167.
3. T. Suzuki and S. Saito: J. Japan Soc. Powders and Powder Met., 18 (1971) 28-33.
4. S. Saito, T. Ishitama and A. Sawaoka: Bull. Tokyo Inst. Of Tech., 120 (1974) 137-142.
5. Z. Hara and K. Akechi: Titanium'80, (1982) 2265-2274.