On Thursday, September 11, 2003, at 05:44  PM, Ray Denenberg, Library
of Congress wrote:

> My suggestion is to add an attribute to <location> to indicate if it's
> a
> physical or electronic source (values 'physical' and 'electronic' or
> please
> suggest alternative values); in the latter case a URL would be assumed.

Good idea!

I note Ralph's question about why not explicitly code this as a URL,
and don't have firm option, but am guessing it's a question of
simplicity.  What would be the implications of allowing URL?  Are there
other electronic locations that might be relevant?