@article{24939,
      author       = "Gendt, G. and Montag, H. and Zentralinstitut für Physik
                      der Erde and XXIII. Plenary Meeting of COSPAR Technical
                      Panel on Dynamics of Artificial Satellites and Space Probes,
                      Budapest, June 1980",
      title        = "The Program Systems "Potsdam-4" for Differential
                      Improvement of Orbital Elements and Other Parameters.
                      XXIII.Plenary Meeting of COSPAR Technical Panel on Dynamics
                      of Artificial Satellites and Space Probes, Budapest, June
                      1980  ",
      year         = "1980",
      note         = "1 sv., 14 liter.",
}