Lovins (2018)
Also: Lovins 2018
How big is the energy efficiency resource?
Lovins, A. B. (2018). How big is the energy efficiency resource?. Environmental Research Letters, 13(9), 090401 Full paper
https://doi.org/10.1088/1748-9326/aad965
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.