@article{Clette:1330,
      author        = "Clette, F. and Lefèvre, L. and Svalgaard, L. and Cliver,
                       E.W. and Vaquero, J.M.",
      title         = "{The new Sunspot and Group Numbers:  A full
                       recalibration}",
      month         = "Aug",
      year          = "2015",
}