1. Pocket Guide to World Zinc (IZA, 1996).
2. Statistical Yearbook (New York, United Nations, 1995), p. 517.
3. L.M. Southwick, EPD Congress 1998, ed. B. Mishra (Warrendale, PA: TMS, 1998), pp. 465–484.
4. L.M. Southwick, JOM, 50 (7) (1998), pp. 21–26.
5. P.J. Koros, I&SM, 23 (1) (1996), pp. 21–27.