1. Maedche, A., Staab, S.: Ontology learning. In: Staab, S., Studer, R. (eds.) Handbook on Ontologies, pp. 173–189. Springer, New York (2004)
2. Hoekstra, R.: The knowledge reengineering bottleneck. J. Semant. Web 1(1,2), 111–115 (2010)
3. Baader, F., Calvanese, D., Mcguinness, D.L., Nardi, D., Patel-Schneider, P.F.: The Description Logic Handbook: Theory, Implementation, and Applications. Cambridge University Press, New York (2003)
4. Baader, F., Brandt, S., Lutz, C.: Pushing the $${\cal {EL}}$$ envelope. In: Proceedings of IJCAI-05 (2005)
5. Lecture Notes in Computer Science;L Raedt De,1993