GRB 090426, RIMOTS optical upper limits. Kono, K. ; Noda, K. ; Sonoda, E. ; Ohmori, N. ; Hayasi, H. ; Daikyuji, A. ; Nisioka, Y. ; Yamauchi, M. Abstract Publication: GRB Coordinates Network Pub Date: 2009 Bibcode: 2009GCN..9257....1K