| Affiliation: |
| AA(Istituto di Fisica Cosmica del CNR, Via Bassini 15, I-20133 Milano, Italy ), AB(ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München, Germany ), AC(Osservatorio Astronomico di Merate, v. E. Bianchi 46, I-22055 Merate (LC), Italy ), AD(Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes MK7 6AA ), AE(Osservatorio Astronomico di Roma, Via Frascati 23, I-00040 Monteporzio Catone (Roma), Italy ), AF(MPI Extraterrestrische Physik, D-85740 Garching, Germany ), AG(Observatorio Astronómico Nacional, Apartado Postal 877, 22800 Ensenada, BC, México), AH(Osservatorio Astronomico di Roma, Via Frascati 23, I-00040 Monteporzio Catone (Roma), Italy ) |