1. Fraunhofer IAF, Fraunhofer Institute for Applied Solid State Physics, Freiburg im Breisgau, Germany
2. Max Planck Institute for Radio Astronomy, Bonn, Germany
3. INAF (National Institute for Astrophysics)-Astronomical Observatory of Cagliari, Selargius, Italy
4. Institut de Radioastronomie Millimétrique, Saint Martin d’Hères, France