@article{668,
      author       = "Heiskanen, W. A. and l´onziéme Assemblée Générale de
                      l´Union Géodésique et Geophysique Internationale Toronto,
                      3 - 14 Septembre 1957",
      title        = "Achievements of the world - wide gravity program of the
                      mapping and charting research laboratory of the Ohio State
                      University  ",
      year         = "1957",
      note         = "1 sv.",
}