@article{1220,
      author       = "Georgijev, N. and Chapanov, J. and Bulgar. Acad. Sciences
                      Sofia and 19. IUGG - Vancouver, Aug. 9-22, 1987",
      title        = "An analytical theory of an intermediate orbit base for
                      geodynamics purposes  ",
      year         = "1987",
      note         = "Obr. v textu. - Liter, 1 sv.",
}