@article{4007,
      author       = "Marek, K. H. and IUGG - IAG, 15th General Assembly MOscow,
                      1 - 14 August 1971",
      title        = "Centering calculation of direction - and range -
                      measurements to satellites in case of tracking -
                      observations  ",
      year         = "1971",
      note         = "1 sv., 1 sv.",
}