@article{21355,
      author       = "Wassef, A. M. and Messih, F. Z. A. and International Union
                      of Geodesy and Geophysics - XII General Assembly Helsinki 25
                      July - 6 August 1960",
      title        = "On the Problem of Weighting in the Statistical Analysis of
                      Levelling Errors  ",
      year         = "1960",
      note         = "1 sv., International Association of Geodesy - United Arab
                      Republik",
}