WTO Trade & Environment
http://www.wto.org/english/tratop_e/envir_e/envir_e.htm

North American Commission for Environmental Cooperation (NAFTA)
http://www.cec.org/home/index.cfm?varlan=english

IISD Environment & Trade Handbook
http://www.iisd.org/trade/handbook/

GETS
http://www.gets.org/

Earth Justice International Trade and Environment
http://www.earthjustice.org/regional/international/?show=Trade and Environment

Trade&environment.org
http://www.trade-environment.org/