Higashiyama, Shohei, Blondel Mathieu, Kazuhiro Seki, and Kuniaki Uehara. “Cost-Sensitive Structured Perceptron Incorporating Category Hierarchy for Named Entity Recognition”. Journal of Information and Communication Technology 14 (April 28, 2015): 1–20. Accessed October 17, 2026. https://e-journal.uum.edu.my/index.php/jict/article/view/8153.