CCSP, 2009: Past Climate Variability and Change in the Arctic and at High Latitudes. A report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. [Alley R.B., Brigham-Grette J., Miller G.H., Polyak L., and White J.W.C.]. U.S. Geological Survey, Department of the Interior, Washington D.C., USA.