Zhu, H., Nan, F., Wang, Z., Nallapati, R. and Xiang, B. (2020) “Who Did They Respond to? Conversation Structure Modeling Using Masked Hierarchical Transformer”, Proceedings of the AAAI Conference on Artificial Intelligence, 34(05), pp. 9741-9748. doi: 10.1609/aaai.v34i05.6524.