Atmospheric composition 1 million years ago from blue ice in the Allan Hills, Antarctica

Higgins, John A, Andrei V Kurbatov, Nicole E Spaulding, Ed Brook, Douglas S Introne, Laura M Chimiak, Yuzhen Yan, Paul A Mayewski, and Michael L Bender. 2015. Atmospheric Composition 1 Million Years Ago From Blue Ice In The Allan Hills, Antarctica. Proceedings Of The National Academy Of Sciences. Proceedings Of The National Academy Of Sciences. doi:http://www.pnas.org/content/early/2015/05/06/1420232112.abstract. http://carboncycle.princeton.edu/sites/default/files/pdfs/Higgins_2015_PNAS_atmospheric.pdf.