F. Brahman, and S. Chaturvedi. Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), page 5277--5294. Online, Association for Computational Linguistics, (November 2020)
E. Clark, Y. Ji, and N. Smith. Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long Papers), 1, page 2250--2260. (2018)