H. Li, F. Xu, and H. Uszkoreit. Proceedings of the International Conference on Recent Advances in Natural Language Processing 2011 (RANLP 2011), page 660-665. RANLP 2011 Organising Committee, (2011)
J. Qin, J. Xu, D. Hu, M. Sageman, and H. Chen. Intelligence and Security Informatics, volume 3495 of Lecture Notes in Computer Science, Springer, Berlin / Heidelberg, (2005)