Reference:Keeling and Whorf 2004
From Global Warming Art
Keeling, C.D. and T.P. Whorf (2004). "Atmospheric CO2 records from sites in the SIO air sampling network" in Trends: A Compendium of Data on Global Change. Oak Ridge, Tenn., U.S.A.: Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy.
The following pages on Global Warming Art refer to this reference: