Solanki et al. (2004)

Also: Solanki et al. 2004, Solanki 2004

Unusual activity of the Sun during recent decades compared to the previous 11,000 years

Solanki, S. K., Usoskin, I. G., Kromer, B., Schüssler, M., & Beer, J. (2004). Unusual activity of the Sun during recent decades compared to the previous 11,000 years. Nature, 431(7012), 1084-1087. Link to paper

doi:10.1038/nature02995

References