http://www.v-c-s.org/
http://cdm.unfccc.int/
http://cdmrulebook.org/
http://en.wikipedia.org/wiki/Emissions_trading
http://ec.europa.eu/clima/policies/ets/index_en.htm
http://www.ecosystemmarketplace.com/
http://cdm.unfccc.int/methodologies/PAmethodologies/approved
http://cdm.unfccc.int/methodologies/SSCmethodologies/approved