GRB130313A: optical observations from GTC. de Ugarte Postigo, A. ; Thoene, C. C. ; Gorosabel, J. ; Sanchez-Ramirez, R. ; Fynbo, J. P. U. ; Tanvir, N. Abstract Publication: GRB Coordinates Network Pub Date: 2013 Bibcode: 2013GCN.14302....1D