GRB 090831B, RIMOTS optical upper limits. Kono, K. ; Daikyuji, A. ; Sonoda, E. ; Ohmori, N. ; Hayasi, H. ; Noda, K. ; Nisioka, Y. ; Yamauchi, M. Abstract Publication: GRB Coordinates Network Pub Date: 2009 Bibcode: 2009GCN..9853....1K