@article{Vrancken:1874,
      author        = "Vrancken, M. and  Hensberge, H. and  David, M. and 
                       Verschueren, W.",
      title         = "{Spectroscopic analysis of early-type stars in young
                       stellar groups. I. Differential analysis of the B1V stars
                       in NGC 2244.}",
      year          = "1997",
}