B. Fonseca, P. Golgher, B. Pôssas, B. Ribeiro-Neto, and N. Ziviani. CIKM '05: Proceedings of the 14th ACM international conference on Information and knowledge management, page 696--703. New York, NY, USA, ACM Press, (2005)
A. Hotho, R. Jäschke, C. Schmitz, and G. Stumme. Proceedings of the 3rd European Semantic Web Conference, volume 4011 of LNCS, page 411-426. Budva, Montenegro, Springer, (June 2006)