Assessment of different sunspot number series using the cosmogenic isotope 44Ti in meteorites
Eleanna Asvestari, Ilya G. Usoskin, Gennady A. Kovaltsov, Mathew J. Owens, Natalie A. Krivova, Sara Rubinetti, Carla Taricco MNRAS (2017) stx190. DOI:https://doi.org/10.1093/mnras/stx190 Published: 22 January 2017 LINK “Many sunspot number series exist suggesting different levels…