A. Rooshenas, A. Kamath, and A. McCallum. Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 2 (Short Papers), 2, page 130--135. (2018)
Y. Liu, and M. Lapata. (2017)cite arxiv:1705.09207Comment: change to one-based indexing, published in Transactions of the Association for Computational Linguistics (TACL), https://transacl.org/ojs/index.php/tacl/article/view/1185/280.