GRB 070621: VLT optical observations. D'Avanzo, P. ; D'Elia, V. ; Fugazza, D. ; Tagliaferri, G. ; Malesani, D. ; Fynbo, J. P. U. Abstract Publication: GRB Coordinates Network Pub Date: 2007 Bibcode: 2007GCN..6574....1D