1. Angles, R., Gutierrez, C.: The expressive power of SPARQL. In: Proceedings of the Seventh International Semantic Web Conference, pp. 114–129 (2008)
2. ARQ. A SPARQL processor for Jena, version 1.3 March 2006, Hewlett-Packard Development Company. http://jena.sourceforge.net/ARQ
3. de Bruijn, J., Franconi, E., Tessaris, S.: Logical reconstruction of normative rdf. In: OWLED
4. Cyganiak, R.: A relational algebra for SPARQL. Tech. Rep. HPL-2005-170, HP-Labs. http://www.hpl.hp.com/techreports/2005/HPL-2005-170.html
5. Durst, M., Suignard, M.: RFC 3987, Internationalized Resource Identifiers (IRIs). http://www.ietf.org/rfc/rfc3987.txt