1. Brickley, D. and Guha, R.V., Resource Description Framework (RDF) Schema Specification, World Wide Web Consortium, 1999.
2. Chaudhri, V.K., Farquhar, A., Fikes, R., Karp, P.D. and Rice, J.P., Open Knowledge Base Connectivity 2.0.3., 1998.
3. Eriksson, H., Fergerson, R.W., Shahar, Y. and Musen, M.A. Automatic generation of ontology editors. In: Twelfth Banff Workshop on Knowledge Acquisition, Modeling, and Management. Banff, Alberta, 1999.
4. Farquhar, A., Fikes, R. and Rice, J., The Ontolingua server: a tool for collaborative ontology construction. International Journal of Human-Computer Studies. 46: p. 707–727, 1997.
5. Grosso, W.E., Eriksson, H., Fergerson, R.W., Gennari, J.H., Tu, S.W. and Musen, M.A. Knowledge modeling at the millennium (the design and evolution of Protégé-2000). In: Twelfth Banff Workshop on Knowledge Acquisition, Modeling, and Management. Banff, Alberta, 1999.