@article{27097,
      author       = "Simonsen, O. and Submitted to the XII General Assembly of
                      the International Union of Geodesy and Geophysic held in
                      Helsinki in 1960",
      title        = "Report from the International Commission for European
                      Levelling for the period September 1957 - July 1960  ",
      year         = "1960",
      note         = "1 sv., International Commission for European Levelling",
}