R. Black, Shun Meat, Says UN Climate Chief, BBC News, 24 May 2011. http://news.bbc.co.uk/2/hi/science/nature/7600005.stm
 E. Hertwich, E. van der Voet, S. Suh, A. Tukker, et al., “Assessing the Environmental Impacts of Consumption and Production: Priority Products and Materials: A Report of the Working Group on the Environmental Impacts of Products and Materials to the International Panel for Sustainable Resource Management,” United Nations Environment Programme, New York, 2010.
 L. D. Frank, M. J. Greenwald, S. Winkelman, J. Chapman and S. Kavage, “Carbonless Footprints: Promoting Health and Climate Stabilization through Active Transportation,” Preventive Medicine, Vol. 50, Suppl. 1, 2010, pp. S99-S105. doi:10.1016/j.ypmed.2009.09.025
 L. D. Frank, J. F. Sallis, T. L. Conway, J. E. Chapman, B. E. Saelens, W. Bachman, “Many Pathways from Land Use to Health: Associations between Neighborhood Walkability and Active Transportation, Body Mass Index, and Air Quality,” Journal of the American Planning Association, Vol. 72, No. 1, 2006, pp. 75-87. doi:10.1080/01944360608976725
 J. Hiskes, “Tailpipe Fumes Are Five Times Worse for Bikers Than for Drivers, Study Finds,” Grist, Accessed 24 May 2011. http://www.grist.org/article/2010-06-08-tailpipe-fumes-are-five-times-worse-for-bikers-than-drivers/
 The Nature Conservancy. “Carbon Footprint Calculator—What’s My Carbon Footprint?” Nature Conservancy, Accessed 24 May 2011 http://www.nature.org/initiatives/climatechange/calculator/
 World Wildlife Fund, “Footprint Calculator,” World Wildlife Fund, 24 May 2011. http://www.footprint.wwf.org.uk/
 University of California Berkeley, “Cool Climate Calculator,” Cool Climate Network, 24 May 2011. http://coolclimate.berkeley.edu/home
 American Heart Association, “Physical Activity Calorie Use Chart,” American Heart Association, 24 May 2011. http://www.americanheart.org/presenter.jhtml?identifier=756
 T. Plate, “Tofu’s Carbon Footprint,” 24 May 2011. http://tofuscarbonfootprint.weebly.com/carbon-calculations.html
 H. Steinfeld, P. Gerber, T. D. Wassenaar, V. Castel, C. deHaan, “Livestock’s Long Shadow; Environmental Issues and Options,” Food and Agriculture Organization of the United Nations, Geneva, 2006.
 C. Foster, K. Green, M. Bleda, et al., “Environmental Impacts of Food Production and Consumption: A Research Report Completed for the Department of Environment, Food and Rural Affairs,” Manchester Business School, London, 2006.
 UNEP/GRID-Arendal, “The Main Greenhouse Gases,” United Nations Environment Program, 24 May 2011. http://www.grida.no/publications/vg/climate/page/3060.aspx
 C. L. Weber, H. S. Matthews, “Food-Miles and the Relative Climate Impacts of Food Choices in the United States,” Environmental Science and Technology, Vol. 50, 2008, pp. 3508-3513. doi:10.1021/es702969f