GRB010921 optical observations. Fox, D. W. ; Burruss, R. ; Berger, E. ; Bloom, J. S. ; Djorgovski, S. G. ; Kulkarni, S. R. ; Haynes, W. M. Abstract Publication: GRB Coordinates Network Pub Date: 2001 Bibcode: 2001GCN..1099....1F