1. Eilers, J. M., Braake, D. F., Landers, D. H., and Kellar, P. E.: 1988, Verh. Internat. Verein Limnol 23, 144.
2. EPA: 1979. Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020.
3. EPA: 1984, The Determination of Inorganic Anions by Ion Chromatography, EPA-600/4-84-017.
4. IBP Handbook;H. L. Golterman,1969
5. Logan, R. M., Derby, J. C., and Duncan, L. C.: 1982, Environ. Sci. and Tech. 16, 771.