1. American Public Health Association, 1992. Standard Methods for the Examination of Water and Waste Water, 20th ed., Clesceri, L. S., Greenberg, A.E., Eaton, A. E. (Eds.), Washington DC, pp. 2.57–2.59.
2. A study of a greenhouse concept on conventional biogas systems for enhancing biogas yield in winter months;Bansal;International Journal Energy Resources,1985
3. Bansal, P.K., Ram, S., Bansal, N.K., 1984. Performance of greenhouse coupled biogas plants in winter months of Northern India. In: Proceedings of World Bio-Energy Conference and Exhibition, Gothernburg, Sweden, pp. 14–19.
4. Methane: Fuel of the Future;Bell,1973
5. Evolving biomass-based biogas plants: the ASTRA experience;Chanakya;Current Science,2004