It seems like it's really "in BIBFRAME only http URIs [or blank nodes]...". These URN things seem to exist to prop up the blank nodes.

On Jun 9, 2016, at 7:25 PM, Ray Denenberg <[log in to unmask]> wrote:

I meant  “...in BIBFRAME only http URIs ….”

On Jun 9, 2016, at 7:16 PM, Simon Spero <[log in to unmask]> wrote:

On Jun 9, 2016 6:43 PM, "Ray Denenberg" <[log in to unmask]> wrote:
>   A Urn is in fact a URI, but that’s irrelevant.  It is not an HTTP URI.   HTTP URIs, and only HTTP URIs, are used to identify resources that are subjects or objects of RDF statements.

That's not strictly correct.
Resource names in subjects or objects can be any absolute IRI. See §3.2 of the RDF concepts and Abstract Syntax recommendation for details.

The IRI <ftp://chickens.org/��> is perfectly valid in  subject, predicate, or object positions.

Simon