[1] UNIV MASSACHUSETTS,DEPT PHYS & ASTRON,AMHERST,MA 01002
[2] PAHLAVI UNIV,DEPT PHYS,SHIRAZ,IRAN
[3] NATL RADIO ASTRON OBSERV,CHARLOTTESVILLE,VA
[4] HARVARD COLL OBSERV,CTR ASTROPHYS,CAMBRIDGE,MA 02138
[5] SMITHSONIAN ASTROPHYS OBSERV,CAMBRIDGE,MA
[6] YORK UNIV,DEPT PHYS,TORONTO,ONTARIO,CANADA
[7] YORK UNIV,CRESS,TORONTO,ONTARIO,CANADA
[8] BYURAKAN ASTROPHYS OBSERV,BYURAKAN,ARSSR