@article{1800,
      author       = "Keating, Terrence J. and Wolf, Paul R. and XIII. Congress
                      of the International Society for Photogrammetry, Helsinki,
                      1976. Commission III",
      title        = "Anylytical Photogrammetry from Digitized Image Densities  ",
      year         = "1976",
      note         = "1 sv.",
}