1. Climate Change 2007: Mitigation of Climate Change. IPCC Fourth Assessment Report (AR4)http://www.ipcc.ch/publications_and_data/ar4/wg3/en/contents.html
2. Climate change 2007: The Physical Science Basis. IPCC Fourth Assessment Report (AR4)http://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html
3. Livestock methane emission: From the individual grazing animal through national inventories to the global methane cycle;Lassey;Agric. Forest Meteorol.,2007
4. The history of energetic efficiency research: Where have we been and where are we going?;Johnson;J. Anim. Sci.,2003
5. Animal and Human Calorimetry;Mclean,1987