Progressively Pretrained Dense Corpus Index for Open-Domain Question Answering Wenhan Xiong author Hong Wang author William Yang Wang author 2021-04 text Proceedings of the 16th Conference of the European Chapter of the Association for Computational Linguistics: Main Volume Paola Merlo editor Jorg Tiedemann editor Reut Tsarfaty editor Association for Computational Linguistics Online conference publication xiong-etal-2021-progressively 10.18653/v1/2021.eacl-main.244 https://aclanthology.org/2021.eacl-main.244/ 2021-04 2803 2815