M. Xiao, and Y. Guo. Proceedings of the Seventeenth Conference on Computational Natural Language Learning, page 1--9. Sofia, Bulgaria, Association for Computational Linguistics, (August 2013)
R. Chattopadhyay, W. Fan, I. Davidson, S. Panchanathan, and J. Ye. Proceedings of the 30th International Conference on Machine Learning (ICML-13), 28, page 253-261. JMLR Workshop and Conference Proceedings, (May 2013)