@article{Halbwachs:2374,
      author        = "Halbwachs, J.-L. and  Piquard, S. and  Virelizier, P. and 
                       Cuypers, J. and  Lampens, P. and  Oblak, E.",
      title         = "{A Statistical Study of the Visual Double Stars in the
                       TYCHO Catalogue}",
      year          = "1997",
}