1. Reusing Design Knowledge;Ahmed,2006
2. Ontological modelling for designing Educational systems;Breuker,1999
3. DARPA (Defense Advanced Research Projects Agency) (2006), DAML ontology repository, Available online (link checked on Jan, 26, 2006) [http://www.daml.org/ontologies/]
4. Friedman-Hill E. (2006) “Jess: the Java Expert System Shell”, Sandia National Laboratories, (link checked on 12th, May, 2006) [http://herzberg.ca.sandia.gov/jess/]
5. A translation approach to portable ontology specifications.;Gruber;Knowledge Adquisition,1993