Clark, P.U.. «Executive Summary». A: Abrupt Climate Change. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. Reston, Virginia, USA: U.S. Geological Survey, desembre 2008., pp. 163–201. Report websiteArxivat 2013-05-04 a Wayback Machine.
Clark, P.U.. «Executive Summary». A: Abrupt Climate Change. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. Reston, Virginia, USA: U.S. Geological Survey, desembre 2008., pp. 163–201. Report websiteArxivat 2013-05-04 a Wayback Machine.
Clark, P.U.. «Executive Summary». A: Abrupt Climate Change. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. Reston, Virginia, USA: U.S. Geological Survey, desembre 2008., pp. 163–201. Report websiteArxivat 2013-05-04 a Wayback Machine.