R. Cole, P. Eklund, и B. Groh. International Symposium on Knowledge Retrieval, Use, and Storage for Efficiency, KRUSE-97, стр. 151-164. (1997)Later revised and published completely in Cole's Computational Intelligence paper.
A. Hotho, R. Jäschke, C. Schmitz, и G. Stumme. Proceedings of the 3rd European Semantic Web Conference, стр. 411-426. Budva, Montenegro, Springer, (июня 2006)
D. Puppin, и F. Silvestri. CIKM '06: Proceedings of the 15th ACM international conference on Information and knowledge management, стр. 880--881. New York, NY, USA, ACM, (2006)