Xu, Yongxiu, Heyan Huang, Chong Feng, and Yue Hu. “A Supervised Multi-Head Self-Attention Network for Nested Named Entity Recognition”. Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 16 (May 18, 2021): 14185-14193. Accessed April 25, 2024. https://ojs.aaai.org/index.php/AAAI/article/view/17669.