Frequently Asked Questions - LCCN Permalink

What are LCCN Permalinks?

LCCN Permalinks are persistent URLs for bibliographic records in the LC Catalog and authority records in LC Authorities. These links are constructed using the record's LCCN (or Library of Congress Control Number), an identifier assigned by the Library of Congress to bibliographic and authority records. LCCN Permalinks are also available for citation records in the Handbook for Latin American Studies (HLAS).

How can I use LCCN Permalinks?

The LCCN Permalink web service offers an easy way to cite and link to bibliographic records in the LC Catalog, authority records in LC Authorities, and citation records in the Handbook for Latin American Studies (HLAS). You can use an LCCN Permalink anywhere you need to reference an LC bibliographic, authority, or HLAS citation record — in emails, blogs, databases, web pages, digital files, etc.

How do I bookmark an LCCN Permalink record display?

Just right-click on the LCCN Permalink web page and select appropriate options in your browser to copy the link, bookmark the page, or add the page to your favorites list.

I have a valid LCCN. However, LCCN Permalink reports that the LCCN I submitted was not found in the LC Catalog. Why am I receiving this error message?

LCCN Permalink retrieves and displays bibliographic records found in the LC Catalog and authority records in LC Authorities. Not all LCCNs assigned by the Library of Congress, however, resolve to an LC record. The Library of Congress began assigning LC control numbers in 1898. Some LCCNs may have been deleted from the Catalog, some LCCNs from older printed catalog cards may not yet have online records. LCCNs are also assigned before publication to items which the Library may subsequently decide not to add to its collections — including items cataloged by the National Library of Medicine or the National Agricultural Library, many large-print books, serials cataloged through the cooperative CONSER program, and items which received preassigned control numbers (PCNs). While LCCN Permalink may not find a bibliographic record in the LC Catalog, these LCCN may be represented in other library databases.

How does LCCN Permalink work?

LCCN Permalinks are constructed using the following syntax:

https://lccn.loc.gov/  followed by the  normalized LCCN
Examples:  https://lccn.loc.gov/2003556443  or  https://lccn.loc.gov/n79018774

The LCCN query (based on the Bath Profile syntax) searches both valid and cancelled LCCNs (MARC21 fields 010a and 010z). LCCN Permalinks for bibliographic records in the LC Catalog and citation records in the Handbook for Latin American Studies (HLAS) redirect you to full record displays in their respective catalogs. LCCN Permalinks for authority records are retrieved and processed by an XML stylesheet to create an LCCN Permalink display. When qualified with a defined XML format (see next question), these identifiers use the Z39.50/SRU gateways for the LC Catalog and Handbook for Latin American Studies (HLAS) to retrieve records formatted in standard XML formats. LCCN Permalink can present bibliographic records in BIBFRAME, MARCXML, MODS, and Dublin Core formats; and authority records in MARCXML. In addition, name and subject authority records are linked to LC Authorities & Vocabularies. Where possible, name authorities are also linked to the Virtual International Authority File (VIAF) . LCCN Permalinks for bibliographic records reflect daily updates; name and subject authority record links are updated weekly.

How do I link directly to the BIBFRAME, MARCXML, MODS, or Dublin Core formats of LCCN Permalink?

LCCN Permalink provides a qualified URL syntax to support direct persistent links to BIBFRAME, MARCXML, MODS, or Dublin Core-formatted bibliographic records. The qualifier must be added to the end of the LCCN Permalink URL. For example: https://lccn.loc.gov/2003556443/mods

The following LCCN Permalink qualifiers are currently supported:

XML Format	Qualifier
BIBFRAME	/bibframe2
MARCXML	/marcxml
MODS	/mods
Dublin Core	/dc

Are MARC21 records available from LCCN Permalink?

LCCN Permalink bibliographic record displays provide a link to the MARC21 UTF-8 record in the LC Catalog. Clicking on this link triggers browser-dependent options for locally saving the MARC21 record.

How does LCCN Permalink normalize LCCNs?

LC Permalink uses info:lccn URI specifications to normalize the standard LCCN syntax. Each LCCN has three components: a prefix, year, and serial number. Prefixes may be blank, or they may contain from one to three lowercase alphabetic characters (maintained in a controlled list). Year information is either two or four digits — two digits for LCCNs assigned through 2000, four digits for LCCNs assigned 2001 and later. LCCN serial numbers contain six digits.

The info:lccn normalization removes hyphens, left-fills serial numbers with zeros, and removes spaces in LCCN prefixes. The resulting LCCNs may look different from LCCNs appearing in the MARC 010 fields of bibliographic records, in Cataloging-in-Publication data, or on printed catalog cards.

My LCCN Permalink display contains some strange characters, such as boxes. Why?

While authority records from LC Authorities will display correctly for most languages without changing your preferred browser settings, you may see boxes or incorrectly formatted characters if your browser is set to display mainly English language web pages. LCCN Permalink displays are best viewed using Unicode fonts and the most current browser and operating system software.

What should I do when I receive a system error message?

If LCCN Permalink is temporarily unavailable, please first try to refresh the display in your browser. If problems persist, please send a problem report to the Library through Ask a Librarian.

What are the permissible rates for accessing LCCN Permalink?

As an SRU-based web service supporting the LC Catalog metadata, LCCN Permalink must ensure that access to the Catalog's SRU/Z39.50 gateways remain accessible to all Library patrons. Current LCCN Permalink guidelines do not permit robots and recommend that software programs submit a total of no more than 10 requests per minute, regardless of the number of machines used to submit requests. The Library reserve the right to terminate programs that require more than 24 hours to complete and to block IP addresses that fail to honor the LCCN Permalink's robots.txt file. See: https://www.loc.gov/legal/#security

How do I obtain an LCCN for my publication?

The Library of Congress offers U.S. book publishers the service of assigning LCCNs to their prepublication titles through the Preassigned Control Number (PCN) Program. Qualified publishers may also receive an LCCN as part of CIP data issued by the Cataloging in Publication (CIP) Program. LCCNs are also assigned by the Library of Congress to items added to the Library's collections or cataloged as part of the cooperative CONSER program. As noted above, the assignment of an LCCN by the Library of Congress does not automatically ensure that a publication will be selected for Library's collections.

Where can I go for help if this FAQ does not resolve my question or problem?

If you are a researcher in a Library of Congress reading room, please ask the reference librarian on duty for help. You may also report problems by contacting the Library of Congress through Ask a Librarian.