External Links
Environmental Tracer Group, Lamont-Doherty Earth Observatory
http://www.ldeo.columbia.edu/~noblegas
Alternative Fluorocarbons Environmental Acceptability Study
http://www.afeas.org
ALE/GAGE/AGAGE Network
http://cdiac.esd.ornl.gov/ndps/alegage.html
NOAA Earth System Research Laboratory, Global Monitoring Division
http://www.cmdl.noaa.gov
NOAA National Climatic Data Center
http://www.ncdc.noaa.gov
Environmental Isotope Laboratory, University of Waterloo
http://www.uweilab.ca
U.S. Geological Survey Isotope Tracers Project
http://wwwrcamnl.wr.usgs.gov/isoig
Reston Stable Isotope Laboratory -- Isotope Fractionation Project
http://isotopes.usgs.gov
