1. The Department of Alternative Energy Development and Efficiency (DEDE), 1992. The Study of the Direction of Energy Used in Rural Area in Thailand in 1991. Bangkok, Thailand.
2. King Mongkut's University of Technology Thonburi, Thailand, 2002. The Project of Development and Implementation of ICS.
3. Department of Agricultural Extension (DoAE), 2001. The Implementation to Produce the Biogas from Animal's Waste Project for Energy Substitution and Environmental Improvement Phase II. Bangkok, Thailand.
4. Department of Agricultural Extension (DoAE). The Manual of Calculation for Construction of the Fix-dome Type of Biogas. Bangkok, Thailand.
5. Environmental Change Institute, University of Oxford, 2005. Workable Metrics for the EU Emissions Trading Scheme, Introduction to Climate Metrics. Available online: http://www.eci.ox.ac.uk/lowercf/ukerc/event2introdimatemetrics.htm.; 2/1/2005.