GRB 171120A: Xinglong-2.16m optical upper limit. Zhu, Z. P. ; Feng, H. X. ; Xu, D. ; Zhao, Y. ; Xiao, F. ; Qian, S. B. ; Hu, Y. D. Abstract Publication: GRB Coordinates Network Pub Date: 2017 Bibcode: 2017GCN.22145....1Z