1. Baltic Institute of Technology, al. Zwycistwa 96/98, PL-81-451 Gdynia, Poland
2. European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München, Germany
3. Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
4. Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife, Spain
5. Departamento de Astrofísica, Universidad de La Laguna, E-38200 La Laguna, Tenerife, Spain
6. Kapteyn Astronomical Institute, University of Groningen, Postbus 800, NL-9700 AV Groningen, the Netherlands
7. Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstrasse 12-14, D-69120 Heidelberg, Germany