1. National Aeronautics and Space Administration (NASA), NASA GISS: NASA news & Feature Releases: NASA, NOAA data show 2016 warmest Year on Record globally, (n.d.). https://www.giss.nasa.gov/research/news/20170118/(accessed March 4, 2019).
2. Climate Change 2014. Mitigation of Climate Change;Intergovernmental Panel on Climate Change (IPCC),2014
3. Food and Agriculture Organization of the United Nations – Statistics Division (FAOSTAT), Emisiones de gases de efecto invernadero de la agricultura, la silvicultura y otros usos de la tierra, (n.d.). http://www.fao.org/assets/infographics/FAO-Infographic-GHG-LatinAmerica-es.pdf..
4. A technological overview of biogas production from biowaste;Achinas;Engineering,2017
5. Life cycle assessment of biogas production through anaerobic co-digestion of nopal cladodes and dairy cow manure;Ramírez-Arpide;J. Clean. Prod.,2018