1. B. W. Morris, C. A. Hardisty, J. F. McCann, G. J. Kamp and T. W. May,Atomic Spectrosc. 6 (1985) 149.
2. R. A. Anderson, M. M. Polansky, N. A. Bryden, K. Y. Patterson, C. Veillon and W. H. Glinsmann,J. Nutrit. 113 (1983) 276.
3. ?International Standards for Drinking Water,? 3rd edn, WHO, Geneva (1971).
4. ?European Standards for Drinking Water,? 2nd edn, WHO Regional Office for Europe, Copenhagen (1970).
5. T. T. Taylor,Chem. Eng. Progr. 79 (1982) 70.