[1] INST NACL TECNICA AEROESPACIAL,LAB ASTROFIS ESPACIAL & FIS FUNDAMENTAL,MADRID 28080,SPAIN
[2] CSIC,INST ASTROFIS ANDALUCIA,E-18080 GRANADA,SPAIN
[3] NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801
[4] HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138
[5] CALTECH,JET PROP LAB,PASADENA,CA 91109
[6] CNR,IST RADIOASTRON,I-40129 BOLOGNA,ITALY
[7] JOINT INST VLBI EUROPE,NL-7990 AA DWINGELOO,NETHERLANDS
[8] LEIDEN OBSERV,NL-2300 RA LEIDEN,NETHERLANDS
[9] CNR,IST RADIOASTRON,I-96017 NOTO,ITALY
[10] USN,RES LAB,REMOTE SENSING DIV,COD 7214,WASHINGTON,DC 20375
[11] MIT,HAYSTACK OBSERV,WESTFORD,MA 01886