Reference:Etheridge et al. 1998
From Global Warming Art
D.M. Etheridge, L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M. Barnola and V.I. Morgan (1998). "Historical CO2 records from the Law Dome DE08, DE08-2, and DSS ice cores" 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: