Gregory et al. (2002)
Also: Gregory et al. 2002
An Observationally Based Estimate of the Climate Sensitivity
Gregory, J. M., Stouffer, R. J., Raper, S. C. B., Stott, P. A. & Rayner, N. A. (2002). An Observationally Based Estimate of the Climate Sensitivity. Journal of Climate. 15(22),3117-3121. PDF
https://doi.org/10.1175/1520-0442(2002)0152.0.co;2
References
All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.