GRB 141221A: Swift detection of a burst with an optical counterpart. Sonbas, E. ; Cummings, J. R. ; D'Elia, V. ; Izzo, L. ; Lien, A. Y. ; Page, K. L. ; Sbarufatti, B. ; Siegel, M. H. Abstract Publication: GRB Coordinates Network Pub Date: 2014 Bibcode: 2014GCN.17206....1S