Speth, James G. The Bridge at the Edge of the World: Capitalism, the Environment, and Crossing from Crisis to Sustainability. Yale School of Forestry & Environmental Studies - Masters of Environmental Management. Web. 27 Feb. 2011. <http://environment.yale.edu/news/5647/>.
نسخة محفوظة 2020-11-29 على موقع واي باك مشين.
yale.edu
environment.yale.edu
Speth, James G. The Bridge at the Edge of the World: Capitalism, the Environment, and Crossing from Crisis to Sustainability. Yale School of Forestry & Environmental Studies - Masters of Environmental Management. Web. 27 Feb. 2011. <http://environment.yale.edu/news/5647/>.
نسخة محفوظة 2020-11-29 على موقع واي باك مشين.