L. Specia, and E. Motta. Proc. of the European Semantic Web Conference (ESWC2007), volume 4519 of LNCS, page 624-639. Berlin Heidelberg, Germany, Springer-Verlag, (July 2007)
D. Ramage, P. Heymann, C. Manning, and H. Molina. WSDM '09: Proceedings of the Second ACM International Conference on Web Search and Data Mining, page 54--63. New York, NY, USA, ACM, (2009)