Zeitschriftenartikel
Asvestari, E.; Usoskin, I. G.; Kovaltsov, G. A.; Owens, M. J.; Krivova, N. A.; Rubinetti, S.; Taricco, C.: Assessment of different sunspot number series using the cosmogenic isotope Ti-44 in meteorites. Mon. Not. Roy. Astron. Soc.
467 (2), S. 1608 - 1613 (2017)