1. The Description Logic Handbook,2003
2. Modern Information Retrieval;Baeza-Yates,1999
3. A. Balmin, V. Hristidis, Y. Papakonstantinou, ObjectRank: Authority-based keyword search in databases, in: Proceedings VLDB-2004, Morgan Kaufmann, 2004, pp. 564–575.
4. J. Bao, E.F. Kendall, D.L. McGuinness, E.K. Wallace, OWL2 Web ontology language: Quick reference guide, 2008. .
5. T. Berners-Lee, Weaving the Web. Harper, San Francisco, CA, 1999.