1. Determination of ozone in water by the indigo method
2. 4. Clesceri, L. S., Greenberg, A. E. and Trussell, R. R. 1989. Standard methods for the examination of water and wastewater, 17th edn., Publ. by American Public Health Association, American Water Works Association and Water Pollution Control Federation, Washington D. C., 4-162 to 4-165.
3. Effect of disinfectants on pathogenic free-living amoebae: in axenic conditions