B. J. Lloyd, Wheeler, D., and Pardon, M.,
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Slow sand filtration : recent developments in water treatment technology, 1988, pp. P. 393-411: fig., tab.
B. J. Lloyd, Wheeler, D., and Bartram, J.,
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Slow sand filtration : recent developments in water treatment technology, 1988, pp. P. 207-229: fig., tab.