@article{Lefèvre:1293,
      author        = "Lefèvre, L. and Carrasco, Victor and Vaquero, J.M. and
                       Gallego, Maricruz",
      title         = "{Equivalence relations between the Cortie and Zurich
                       sunspot group morphological classifications}",
      month         = "Mar",
      year          = "2015",
}