1. Third Assesment Report: Climate Change 2001 Geneva, Switzerland International Panel on Climate Change http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/;2001
2. Test and quality assurance plan: electrical power and heat production using renewable biogas at a dairy farm Research Triangle Park, NC Greenhouse Gas Technology Center https://archive.epa.gov/nrmrl/archive-etv/web/pdf/600etv07058.pdf
3. Beaulieu M Manure management in Canada http://publications.gc.ca/Collection/Statcan/21-021-M/21-021-MIE2004001.pdf;2004
4. Simakov DSA Renewable synthetic fuels and chemicals from carbon dioxide 2017