Song, Kaiqiang, Bingqing Wang, Zhe Feng, Ren Liu, and Fei Liu. 2020. “Controlling the Amount of Verbatim Copying in Abstractive Summarization”. Proceedings of the AAAI Conference on Artificial Intelligence 34 (05):8902-9. https://doi.org/10.1609/aaai.v34i05.6420.