@inproceedings{xiong_wang_wang_2021, 
  title={Progressively Pretrained Dense Corpus Index for Open-Domain Question Answering}, 
  DOI={10.18653/v1/2021.eacl-main.244}, 
  publisher={Association for Computational Linguistics}, 
  author={Xiong, Wenhan and Wang, Hong and Wang, William Yang}, 
  year={2021}
  }