1. Standard Methods for the Examination of Water and Wastewater;APHA, AWWA and WPCF,1985
2. Nitrogen removal by modified activated sludge process;Balakrishnan,1970
3. Effect of inhibitors on nitrification in the activated-sludge process;Downing;J. Inst. Swge Purif.,1964
4. Inhibition of nitrification effects of selected organic compounds;Hockenbury;J. Wat. Pollut. Control Fed.,1977
5. The ecology of nitrification/denitrification systems in activated sludge;Kiff;Wat. Pollut. Control,1972