Zhou, Y. et al. 2021. What the Role is vs. What Plays the Role: Semi-Supervised Event Argument Extraction via Dual Question Answering. Proceedings of the AAAI Conference on Artificial Intelligence. 35, 16 (May 2021), 14638–14646. DOI:https://doi.org/10.1609/aaai.v35i16.17720.