[1] OSSERV ASTRON PADOVA,I-35122 PADUA,ITALY
[2] SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218
[3] ROYAL GREENWICH OBSERV,CAMBRIDGE CB3 0EZ,ENGLAND
[4] EUROPEAN SO OBSERV,W-8046 GARCHING,GERMANY
[5] CNRS,ASTRON SPATIALE LAB,F-13012 MARSEILLE,FRANCE
[6] UNIV COLL CARDIFF,DEPT PHYS,CARDIFF CF1 3TH,WALES
[7] SPACE RES INST,3584 CA UTRECHT,NETHERLANDS
[8] UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720
[9] EUROPEAN SPACE AGCY,DEPT SPACE SCI,DIV ASTROPHYS,2200 AG NOORDWIJK,NETHERLANDS
[10] UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND
[11] MAX PLANCK INST RADIOASTRON,W-5300 BONN 1,GERMANY
[12] OSSERV ASTRON PADOVA,PADUA,ITALY
[13] HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138