Information Retrieval 25th China Conference, CCIR 2019, Fuzhou, China, September 20-22, 2019, Proceedings - Zhang, Qi; Zhang, Qi; Liao, Xiangwen; Liao, Xiangwen; Ren, Zhaochun; Ren, Zhaochun (Springer International Publishing : Imprint: Springer, 2019)