GRB 090518 - NOT upper limit. Thoene, C. C. ; Kankare, E. ; Fynbo, J. P. U. ; Malesani, D. ; Levan, A. J. ; Jakobsson, P. ; Hjorth, J. Abstract Publication: GRB Coordinates Network Pub Date: 2009 Bibcode: 2009GCN..9423....1T