1. Standard Methods for the Examination of Water and Wastewater;APHA,1975
2. Die Beurteilung von Abwasser und Schlamm mittels TTC;Buksteeg,1966
3. Effect of variable loading on oxygen uptake;Duggan;J. Wat. Pollut. Control Fed.,1976
4. Measurement and validity of oxygen uptake as an activated sludge process control parameter;Edwards;J. Wat. Pollut. Control. Fed.,1982
5. Dehydrogenase enzyme as a parameter of activated sludge activities;Ford,1966