1. Wolf WR, Ihnat M (1985) Evaluation of available certified biological reference materials for inorganic nutrient analysis. In: Wolf WR (ed) Biological reference materials: availability, uses and need for validation of nutrient measurement. Wiley, New York, pp 89?105
2. Miller-Ihli NJ, Wolf WR (1986) Anal Chem 58:3225?3230
3. Report of analysis, reference material 8431a (1989) Mixed diet, NIST. Gaithersburg, MD
4. Iyengar GV, Wolf WR, Tanner JT (1988) Fresenius Z Anal Chem 332:549?551
5. Parr RM et al. (1990) Dietary intakes of trace elements and related nutrients in eleven countries: Preliminary results from an IAEA coordinated research programme. In: Proceedings of 7th International Symposium on Trace Element Metabolism in Man and Animals, Yugoslavia