GRB990907: BeppoSAX follow up and X-ray afterglow. Piro, L. ; Capalbi, M. ; Ricci, R. ; Dadina, M. ; di Ciolo, L. ; de Libero, C. ; Butler, R. C. Abstract Publication: GRB Coordinates Network Pub Date: 1999 Bibcode: 1999GCN...409....1P