M. Ankerst, M. Breunig, H. Kriegel, and J. Sander. International Conference on Management of Data and Symposium on Principles of Database Systems Philadelphia (SIGMOD/PODS 1999), PA, USA - May 31 - June 03, 1999, page 49-60. New York, NY, USA, ACM, (1999)
V. Spitkovsky, H. Alshawi, A. Chang, and D. Jurafsky. Proceedings of the Conference on Empirical Methods in Natural Language Processing, page 1281--1290. Stroudsburg, PA, USA, Association for Computational Linguistics, (2011)