1. Holdsworth, S.D. 1975. paper presented at the Conference on Effluent Treatment in the Biochemical Industries. 1975, London.
2. Sheffield, C.W., McNary, R.R. and Killingsworth, L.D. Proc. Ind. Waste Conf. Vol. 23, pp.140–153. Purdue Univ.
3. Parker, D.S., Monser, J.R. and Spicher, R.G. Proc. Ind. Waste Conf. Vol. 23, pp.710–739. Purdue Univ.
4. Agardy, F.J., Spicher, R.G. and Orlob, G.T. Proc. Ind. Waste Conf. Vol. 22, pp.699–709. Purdue Univ.