Usage of Dublin Core "relation" element?

While certain Dublin Core elements are obviously used very widely in RDF
documents, I can't track down much real-world use of the "relation" [1]
element. Can anyone point me to some? 
 
thanks,
 
Bob DuCharme
www.snee.com/bob <http://www.snee.com/bob> 
www.rdfdata.org <http://www.rdfdata.org> 
 
[1] http://dublincore.org/documents/usageguide/elements.shtml#relation
<http://dublincore.org/documents/usageguide/elements.shtml#relation>