GRB 980613 optical observations. Diercks, A. ; Deutsch, E. W. ; Stubbs, C. ; Vreeswijk, P. M. ; Galama, T. J. ; van Paradijs, J. ; Robinson, C. ; Kouveliotou, C. Abstract Publication: GRB Coordinates Network Pub Date: 1998 Bibcode: 1998GCN...108....1D