1. Canadell JG, Le Quéré C, Raupach MR, Field CB, Buitenhuis ET, Ciais P, Conway TJ, Gillett NP, Houghton RA, Marland G (2007) Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks. Proc Natl Acad Sci 104:18866–18870. doi: 10.1073/pnas.0702737104 , published online before print October 25, 2007
2. Clarke L, Edmonds J, Jacoby H, Pitcher H, Reilly J, Richels R (2007) Scenarios of greenhouse gas emissions and atmospheric concentrations, sub-report 2.1A of synthesis and assessment product 2.1 by the U.S. climate change science program and the subcommittee on global change research. Department of Energy, Office of Biological and Environmental Research, Washington, DC, p 106
3. Fisher BS, Nakicenovic N, Alfsen K, Corfee Morlot J, de la Chesnaye F, Hourcade J-Ch, Jiang K, Kainuma M, La Rovere E, Matysek A, Rana A, Riahi K, Richels R, Rose S, van Vuuren D, Warren R (2007) Issues related to mitigation in the long term context. In: Metz B, Davidson OR, Bosch PR, Dave R, Meyer LA (eds) Climate change 2007: mitigation. Contribution of working group III to the fourth assessment report of the inter-governmental panel on climate change. Cambridge University Press, Cambridge
4. Forster P, Ramaswamy V, Artaxo P, Berntsen T, Betts R, Fahey DW, Haywood J, Lean J, Lowe DC, Myhre G, Nganga J, Prinn R, Raga G, Schulz M, van Dorland R, Bodeker G, Boucher O, Collins WD, Conway TJ, Dlugokencky E, Elkins JW, Etheridge D, Foukal P, Fraser P, Geller M, Joos F, Keeling CD, Kinne S, Lassey K, Lohmann U, Manning AC, Montzka S, Oram D, O'Shaughnessy K, Piper S, Plattner G-K, Ponater M, Ramankutty N, Reid G, Rind D, Rosenlof K, Sausen R, Schwarzkopf D, Solanki SK, Stenchikov G, Stuber N, Takemura T, Textor C, Wang R, Weiss R, Whorf T (2007) Changes in atmospheric constituents and in radiative forcing. In: Climate change 2007: the physical science basis. Contribution of Working Group I to the 4th Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, USA
5. G8 Summit (2009) Chair’s summary, 10 July 2009. ( www.guitalia2009.it/static/G8_Allegato/Chair_Summary,1.pdf ).