@article {2939,
	title = {The use of Protozoa to indicate changes in the performance of activated-sludge plants.},
	journal = {Water Research.},
	volume = {25},
	year = {1991},
	note = { Records, Ecol., Indicators},
	pages = {633-638},
	author = {Al-Shahwani, S. M. and Horan, N. J.}
}
