1. Inhibition of nitrification by ammonia and nitrous acid;Anthonisen;J. Water Pollut. Contol Fed.,1976
2. APHA, AWWA and WEF (1992) Standard Methods for the Examination of Water and Wastewater, 18th ed. American Public Health Association, American Water Works Association and Water Environment Federation.
3. A study of nitrification utilizing whole micro-organisms immobilised by the PVA-freezing method;Asano;Water Sci. Technol.,1992
4. Comparison of captor system with other fixed-film media nitrification systems;Banerji;Water Pollut. Res. J. Canada,1993
5. Biological Control of Nitrogen in Wastewater Treatment;Barnes,1983