1. A. T. Hodge,Sci. Am. 252 (6) (1985) 114.
2. N. H. Gale and Z. Stos-Gale,244 (6) (1981) 176.
3. D. H. Ward, The AusIMM G. K. Williams Memorial Symposium, Scientific and technological developments in extractive metallurgy [Proc. Conf.], Symposia Series No. 43, Australia (1985) p. 25.
4. S. J. Pedley, R. Widmark, A. O. Adami, H. Maczek, G. Althabegoity, J. D. Bendit and S. A. Hiscock,Tr. Inst. Min. Met. A 92 (1983) 135A.
5. C. A. Sutherland,CIM Bull. 81 (1988) 85.