Update ACL-2019.md

paper lists/ACL-2019.md

@@ -25,6 +25,7 @@
 | On the Word Alignment from Neural Machine Translation        | *Xintong Li, Guanlin Li, Lemao Liu, Max Meng and Shuming Shi* | Problem Analysis                          | -                                |
 | Imitation Learning for Non-Autoregressive Neural Machine Translation | *Bingzhen Wei, Mingxuan Wang, Hao Zhou, Junyang Lin and Xu SUN* | Neural Network Architecture               | https://arxiv.org/abs/1906.02041 |
 | Monotonic Infinite Lookback Attention for Simultaneous Machine Translation | *Naveen Arivazhagan, Colin Cherry, Wolfgang Macherey, Chung-Cheng Chiu, Semih Yavuz, Ruoming Pang, Wei Li and Colin Raffel* | Neural Network Architecture               | https://arxiv.org/abs/1906.05218 |
+| A Lightweight Recurrent Network for Sequence Modeling | *Biao Zhang, Rico Sennrich* | Neural Network Architecture               | https://arxiv.org/abs/1905.13324 |
 | Domain Adaptation of Neural Machine Translation by Lexicon Induction | *Junjie Hu, Mengzhou Xia, Graham Neubig and Jaime Carbonell* | Domain Adaptation                         | https://arxiv.org/abs/1906.00376 |
 | Beyond BLEU:Training Neural Machine Translation with Semantic Similarity | *John Wieting, Taylor Berg-Kirkpatrick, Kevin Gimpel and Graham Neubig* | Problem Analysis               | -                                |
 | An Effective Approach to Unsupervised Machine Translation    | *Mikel Artetxe, Gorka Labaka and Eneko Agirre*               | Low-resource                              | https://arxiv.org/abs/1902.01313 |