The RedlandRdfLibraries http://librdf.org/
Redland is a set of free software libraries that provide support for the ResourceDescriptionFramework (RDF)
The libraries are written in CeeLanguage. There are language bindings for a number of different languages including CeeSharpLanguage, JavaLanguage, ObjectiveCee, PerlLanguage, PythonLanguage, RubyLanguage, ToolCommandLanguage
Mentioned in PracticalRdf (book).
The ContentManagementSystem CollaborativePortalServer has an interface to RedlandRdfLibraries. -- JohnFletcher