1. D. A. TEMPLETON: ‘Mineral commodity summaries’, 196–197; 1993, Washington, DC, Bureau of Mines.
2. S. M. SHELTON: in ‘The metallurgy of zirconium’, (ed. B. Lustman and F. Kerzc,Jr), 59–115; 1955, New York, NY, McGraw-Hill.
3. On the role of carbon in the carbochlorination of refractory oxides