[1] INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND
[2] UNIV LONDON UNIV COLL,DEPT PHYS & ASTRON,LONDON WC1E 6BT,ENGLAND
[3] SRC,RUTHERFORD & APPLETON LABS,ASTROPHYS GRP,ABINGDON,ENGLAND
[4] STOCKHOLM OBSERV,SALTSJOBADEN,SWEDEN
[5] SRC,RUTHERFORD & APPLETON LABS,SLOUGH,ENGLAND
[6] LUND OBSERV,LUND,SWEDEN
[7] ESTEC,DIV ASTRON,ESA VILLAFRANCA SATELLITE TRACKING STN,MADRID,SPAIN
[8] CNR,FIS COSMICA LAB,I-20133 MILAN,ITALY
[9] UNIV OXFORD,DEPT ASTROPHYS,OXFORD,ENGLAND
[10] UNIV CAMBRIDGE,CAVENDISH LAB,CAMBRIDGE CB3 0HE,ENGLAND
[11] UNIV MILAN,IST FIS,I-20133 MILAN,ITALY