Steinfeld, Henning, Pierre Gerber, Tom Wassenaar, Vincent Castel, Mauricio Rosales, Cees de Haan (2006). “Livestock’s long shadow: environmental issues and options”. FAO.org. Food and Agriculture Organization. Aufgerufen am 17.07.2017.

http://www.fao.org/docrep/010/a0701e/a0701e00.HTM