While reviewing some transformed records at BIBFRAME.org, I noticed that class-LCC is a URI, but class-DDC is a text string. FWIW, DDC is available as linked data – see
http://dewey.info – in the event anyone wants to include DDC URIs in their transformations.
Caveat -- A friend at DDC warned that while not all DDC numbers are retrievable to their full build out, the service will return a URI to the closest retrievable number in the hierarchy.
-Nancy