Usoskin et al. (2007)
Also: Usoskin et al. 2007
Grand minima and maxima of solar activity: new observational constraints
Usoskin, I. G., Solanki, S. K., & Kovaltsov, G. A. (2007). Grand minima and maxima of solar activity: new observational constraints. Astronomy & Astrophysics, 471(1), 301-309. Link to PDF
DOI: https://doi.org/10.1051/0004-6361:20077704
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.