@article{UBHD-67502064,
  author={Bien, Reinhold and J{\"a}hrling, Rainer and Wielen, Roland},
  title={Astronomy for the public},
  subtitle={the 'Astronomische Grundlagen f{\"u}r den Kalender'},
  year={1990},
  pages={55},
  language={eng},
  volume={5},
  note={Gesehen am 25.11.2013},
  journal={Abstract series},
}
@incollection{UBHD-67497019,
  author={Wielen, Roland and Bernstein, Hans-Heinrich and Dettbarn, Christian and Hering, Roland and J{\"a}hrling, Rainer and Lenhardt, Helmut and Walter, Hans G.},
  title={A test of preliminary HIPPARCOS parallaxes using photometric parallaxes of distant stars},
  year={1994},
  pages={74-79},
  language={eng},
  isbn={0-521-46240-1 and 978-0-521-46240-2},
  booktitle={Galactic and solar system optical astrometry},
  editor={Morrison, L. V.},
}