Ye, Y., Y. Feng, B. Luo, Y. Lai, and D. Zhao. “Integrating Relation Constraints With Neural Relation Extractors”. Proceedings of the AAAI Conference on Artificial Intelligence, vol. 34, no. 05, Apr. 2020, pp. 9442-9, doi:10.1609/aaai.v34i05.6487.