Yan, Ming, Chenliang Li, Bin Bi, Wei Wang, and Songfang Huang. “A Unified Pretraining Framework for Passage Ranking and Expansion”. Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 5 (May 18, 2021): 4555-4563. Accessed April 25, 2024. https://ojs.aaai.org/index.php/AAAI/article/view/16584.