@article{Grevesse:1914,
      author        = "Grevesse, N. and  Lambert, D. L. and  Sauval, A. J. and 
                       van Dishoeck, E. F. and  Farmer, C. B. and  Norton, R. H.",
      title         = "{Identification of solar vibration-rotation lines of NH
                       and the solar nitrogen abundance}",
      year          = "1990",
}