Cornejo, C. and Wilkie, A.C. (2010). Greenhouse gas emissions and biogas potential from livestock in Ecuador. Energy for Sustainable Development, 14(4):256-266. [PDF]

Marchaim, U. (1992). Biogas processes for sustainable development. Food and Agriculture Organization of the United Nations, Rome, Italy. [URL]

GTZ. Biogas Digest, Volume I, Biogas Basics. [PDF]

GTZ. Biogas Digest, Volume II, Biogas Basics. [PDF]

GTZ. Biogas Digest, Volume III, Biogas Basics. [PDF]

GTZ. Biogas Digest, Volume IV, Biogas Basics. [PDF]

Sasse, L. (1988). Biogas Plants. GTZ. [PDF]

Werner, U., U. Stöhr, N. Hees. (1989). Biogas plants in animal husbandry. GTZ.[PDF]

K. von Mitzlaff. (1988). Engines for Biogas. GTZ. [PDF]

Sasse, L., C. Kellner and A. Kimaro. (1994). Improved biogas unit for developing countries. GTZ. [PDF]

Task Force on Bioconversion of Organic Residues for Rural Communities. (1979). Bioconversion of Organic Residues for Rural Communities. Papers Presented at the Conference on the State of the Art of Bioconversion of Organic Residues for Rural Communities, Held at the Institute of Nutrition of Central America and Panama, Guatemala City, Guatemala, 13 - 15 November 1978. The United Nations University. [URL]

Fulford, D. (1988). Running a biogas programme: a handbook. Intermediate Technology Publications, London.[URL]

Van Buren, A. (1979). A Chinese biogas manual, popularizing technology in the countryside. Intermediate Technology Publications.[URL]