@article{Lefèvre:3020,
      author        = "Lefèvre, Laure and Aparicio, Alejandro and Gallego,
                       Maricruz and Vaquero, Jose",
      title         = "{Recovering a sunspot catalog for the 1914-1920 period
                       from Madrid}",
      month         = "Apr",
      year          = "2016",
}