GRB031220(=H2976): TNG r-band observation of the Chandra X-ray sources. Antonelli, L. A. ; Testa, V. ; Fugazza, D. ; Pedani, M. ; Piro, L. ; Covino, S. ; Masetti, N. ; Malesani, D. Abstract Publication: GRB Coordinates Network Pub Date: 2003 Bibcode: 2003GCN..2503....1A