author        = "Pedicelli, S. and  Bono, G. and  Lemasle, B. and 
                       François, P. and  Groenewegen, M. and  Lub, J. and  Pel,
                       J. W. and  Laney, D. and  Piersimoni, A. and  Romaniello,
                       M. and  Buonanno, R. and  Caputo, F. and  Cassisi, S. and 
                       Castelli, F. and  Leurini, S. and  Pietrinferni, A. and 
                       Primas, F. and  Pritchard, J.",
      title         = "{On the metallicity gradient of the Galactic disk}",
      year          = "2009",