R. Tous, R. García, E. Rodríguez, and J. Delgado. E-Commerce and Web Technologies: 6th International Conference, EC-Web 2005, volume 3590 of LNCS, page 1--10. Heidelberg, DE, Springer, (2005)
J. Scheffczyk, C. Baker, and S. Narayanan. Ontologies and Lexical Resources for Natural Language Processing, Cambridge University Press, Cambridge, MA, (2008)
I. Cruz, H. Xiao, and F. Hsu. Eighth International Database Engineering and Applications Symposium, IDEAS'04, page 217--226. Coimbra, Portugal, Washington, DC: IEEE Computer Society, (2004)