1. APHA, AWWA, WPCF. (1976).Standard Methods for the Examination of Water and Wastewater, 14th edn., Washington DC.
2. Britz, T.J., Noeth, C. & Lategan, P.M. (1988).Water Res. 22, 163?169.
3. Crawford, G.V. & Teletzke, G.H. (1986).Proceedings of the 41st Industrial Waste Conference, Purdue University 196?203.
4. De Zeeuw, W. & Lettinga, G. (1980).Proceedings of the 35 th Industrial Waste Conference, Purdue University, 39?47.
5. Godwin, S.J., Wase, D.A.J. & Forster, C.F. (1982).Process Biochem. 17, 33?34.