1. J. L. Morning: U. S. Bureau of Mines Bulletin 667, pp. 241–52, 1975.
2. K. P. Shaver and S. B. Lasday:Ind. Heating, 1975, vol. 42, no. 1, pp. 10–22.
3. W. A. Scholes:33 Magazine, 1974, vol. 12, no. 12, p. 38.
4. Y. Otani and K. Ichikawa:Proceedings of lNFACON 74, Helen Glen, ed., pp. 31-37, The First International Congress on Ferro-alloys, South African Institute of Mining and Metallurgy, Johannesburg, 1975.
5. W. L. Hunter and D. L. Paulson: U. S. Bureau of Mines Rep. of Investigation 6755,1966,20 pp.