1) The Nature Conservancy, Climate Change, Voluntary Carbon Offsets: Meeting the Highest Standards, http://www.nature.org/initiatives/climatechange/activities/art24030.html
2) ISO 14064-2: Specification with Guidance at the Project Level for Quantification, Monitoring And Reporting Of Greenhouse Gas Emission Reductions, http://www.csa.ca/cm/iso14064-greenhouse-gases