pdf dblp ICTNET at TREC 2019 Complex Answer Retrieval Track Hongfei Ren | Ruibin Xiong | Yutao Zeng | Jiangui Chen | Yinqiong Cai | Haoquan Jiang Proceedings of the Twenty-Eighth Text REtrieval Conference, TREC 2019, Gaithersburg, Maryland, USA, November 13-15, 2019