">special syntax in XML</a> called 
RDF/XML for short. In RDF, every resource, except literals and blank nodes, is 
identified with URI references. This idea originates from the meta-data markup 
for web resources. However, you do not need to mind in Semantic Webs or ontology 
descriptions whether resources in RDF really exist on the Webs or not. </p>
<p class="justify">In theory, a URI reference in RDF denotes an entity in the 
<i>universe of discourse</i>, namely a virtual world that reflects ideas on the