1. Arceivala, S. J., Lakshminarayana, J. S. S., Alagarsamy, S. R., Sastry, C. A., 1970, Waste Stabilisation Ponds, Central Public Health Engineering Research Institute, Nagpur.
2. Barker, H. A., 1956, Bacterial Fermentations, John Wiley and Sons, New York.
3. Benson-Evans, K., Williams, P. F., 1975, Algae and bryophytes, in: Ecological Aspects of Used-Water Treatment, Vol. I (C. R. Curds, H. A. Hawkes, eds.), pp. 153–202, Academic Press, London.
4. Bond, R. G., Straub, C. P., Prober, R. (eds.), 1974, Handbook of Environmental Control, Vol. IV, CRC Press, Cleveland.
5. Bryant, M. P., Wolin, E. A., Wolin, M. J., Wolfe, R. S., 1967, Methanobacillus omelianskii, a symbiotic association of two species of bacteria, Arch. Mikrobiol. 59: 20.