R. Nallapati, A. Ahmed, E. Xing, and W. Cohen. Proceedings of the 14th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, page 542--550. New York, NY, USA, ACM, (2008)
Q. He, B. Chen, J. Pei, B. Qiu, P. Mitra, and L. Giles. Proceedings of the 18th ACM conference on Information and knowledge management, page 957--966. New York, NY, USA, ACM, (2009)