@article{7358,
      author       = "Gay, Ray H. and Grossi, Mario D.",
      title        = "Doppler Measurements of the Ionosphere on the Occasion of
                      the Apollo-Soyuz Test Project. Part II: Inversion of
                      Differential and Rotating Doppler Schifts  ",
      year         = "1975",
      note         = "2x1 sv.",
}