Library of Congress LCCN Permanlinks provide a persistent link to bibliographic records in the Library of Congress catalog.
From the FAQ:
You can use an LCCN Permalink anywhere you need to reference an LC bibliographic record — in emails, blogs, databases, web pages, digital files, etc.
Let’s see how that works: http://lccn.loc.gov/88009251
The internal system maintains its use of the Library of Congress Control Number (the LCCN in the title), which is a unique identifier for that record and allows the outside world access to the same information using a URI.
Question: When I have a work that is identified by a LCCN Permalink and also has an identifier in CiteseerX, DBLP, WorldCat or in a European library, which one should I use?
Question: The FAQ says this link identifies the bibliographic record. Not the same thing as the book it identifies. How should I tell others that I am using the URI to identify a particular book? (Which is not the same thing as the record for that book.)