R. Mehrotra, S. Sanner, W. Buntine, и L. Xie. Proceedings of the 36th international ACM SIGIR conference on Research and development in information retrieval, стр. 889--892. ACM, (2013)
Z. Jianfeng, X. Yunqing, M. Bin, Y. Jianmin, и H. Yu. Proceedings of the 5th International Joint Conference on Natural Language Processing (IJCNLP2011), стр. 589-597. (ноября 2011)