1. ANSI/NISO Z39.19-2005, Guidelines for the construction, format, and management of monolingual controlled vocabularies, National Information Standards Organization, 2005.
2. F. Baader, I. Horrocks and U. Sattler, Description logics, in: Handbook on Ontologies, S. Staab and R. Studer, eds, 2nd edn, Springer, Berlin, Heidelberg, 2009, pp. 21–43.
3. F. Baader and W. Nutt, Basic description logics, in: The Description Logic Handbook: Theory, Implementation, and Applications, F. Baader, D. Calvanese, D.L. McGuinness, D. Nardi and P.F. Patel-Schneider, eds, 2nd edn, Cambridge University Press, Cambridge, 2003, pp. 43–95.
4. BioTop: An upper domain ontology for the life sciences – a description of its current structure, contents and interfaces to OBO ontologies;Beisswanger;Applied Ontology,2008
5. E. Bertino, B. Catania and G.P. Zarri, The Cyc project, in: Intelligent Database Systems, Addison-Wesley Professional, 2001, pp. 275–316.