1. J.T. Chao, P.J. Dugdale, D. R. Morris, and F. R. Steward:Metall. Trans. B, 1978, vol. 9B, pp. 293–300.
2. J.T. Chao:Metall. Trans. B, 1981, vol. 12B, pp. 385–402.
3. R.S. Young:Chemical Analysis in Extractive Metallurgy, Griffin, London, 1971, pp. 185, 196.
4. J. A. Maxwell:Rock and Mineral Analysis, Wiley Interscience, New York, NY, 1968, p. 419.
5. E.G. Moorhead:Standard Methods of Chemical Analysis, 6th edition, N.H. Furman, ed., Van Nostrand, New York, NY, 1962, ch. 25, p. 551.