The NiuTrans Machine Translation Systems for WMT21 Shuhan Zhou author Tao Zhou author Binghao Wei author Yingfeng Luo author Yongyu Mu author Zefan Zhou author Chenglong Wang author Xuanjun Zhou author Chuanhao Lv author Yi Jing author Laohu Wang author Jingnan Zhang author Canan Huang author Zhongxiang Yan author Chi Hu author Bei Li author Tong Xiao author Jingbo Zhu author 2021-11 text Proceedings of the Sixth Conference on Machine Translation Loic Barrault editor Ondrej Bojar editor Fethi Bougares editor Rajen Chatterjee editor Marta R Costa-jussa editor Christian Federmann editor Mark Fishel editor Alexander Fraser editor Markus Freitag editor Yvette Graham editor Roman Grundkiewicz editor Paco Guzman editor Barry Haddow editor Matthias Huck editor Antonio Jimeno Yepes editor Philipp Koehn editor Tom Kocmi editor Andre Martins editor Makoto Morishita editor Christof Monz editor Association for Computational Linguistics Online conference publication zhou-etal-2021-niutrans https://aclanthology.org/2021.wmt-1.26/ 2021-11 265 272