 Citation If you find our work useful, please consider citing our paper: ```bibtex @inproceedings{DBLP:conf/wsdm/MaGZFJC21,   author    = {Xinyu Ma and                Jiafeng Guo and                Ruqing Zhang and                Yixing Fan and                Xiang Ji and                Xueqi Cheng},   editor    = {Liane Lewin{-}Eytan and                David Carmel and                Elad Yom{-}Tov and                Eugene Agichtein and                Evgeniy Gabrilovich},   title     = {{PROP:} Pre-training with Representative Words Prediction for Ad-hoc                Retrieval},   booktitle = {{WSDM} '21, The Fourteenth {ACM} International Conference on Web Search                and Data Mining, Virtual Event, Israel, March 8-12, 2021},   pages     = {283--291},   publisher = {{ACM}},   year      = {2021},   url       = {https://doi.org/10.1145/3437963.3441777},   doi       = {10.1145/3437963.3441777},   timestamp = {Wed, 07 Apr 2021 16:17:44 +0200},   biburl    = {https://dblp.org/rec/conf/wsdm/MaGZFJC21.bib},   bibsource = {dblp computer science bibliography, https://dblp.org} } ```