GRB 131031A: 1.23m CAHA i-band and 1.5m OSN r-band observations of Swift/BAT error circle. Terron, V. ; Gorosabel, J. ; de Ugarte Postigo, A. ; Castro-Tirado, A. J. ; Sota, A. Abstract Publication: GRB Coordinates Network Pub Date: 2013 Bibcode: 2013GCN.15422....1T