[1] MULLARD RADIO ASTRON OBSERV,CAVEVDISH LAB,CAMBRIDGE CB3 0HE,ENGLAND
[2] UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR SPACE SCI,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720
[3] UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND
[4] NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771
[5] INST ASTROFIS CANARIAS,E-38200 LA LAGUNA,SPAIN