@article{Vaquero:3010,
      author        = "Vaquero, J. M.  and Svalgaard, L. and Carrasco, V. M. S.
                       and Clette, F. and Lefèvre, L. and Gallego, M. C. and
                       Arlt, R. and Aparicio, A. J. P. and Richard, J.-G. and
                       Howe, R.",
      title         = "{A Revised Collection of Sunspot Group Numbers}",
      year          = "2016",
      note          = "Sunspot Workshops ",
}