GRB 190311A: NOT optical counterpart. Selsing, J. ; Zhu, Z. P. ; Xu, D. ; Malesani, D. ; Nespral, D. ; Gandolfi, D. ; Telting, J. Abstract Publication: GRB Coordinates Network Pub Date: 2019 Bibcode: 2019GCN.23962....1S