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Leasing Records for Books, Serials, Audiovisuals, and Other Resources (Catfile, CatfilePlus, and Serfile)

NLM offers three bibliographic products derived from the MARC 21 data in LocatorPlus: Catfile, CatfilePlus, and Serfile.

Content and Specifications
NLM bibliographic records for serials, monographs, audiovisuals, computer software, electronic resources and other materials are available on a subscription basis.

Catfile is available in MARC 21 format only.

CatfilePlus and Serfile are available in MARC 21 format.

As of August 2004, CatfilePlus and Serfile are also available in XML format.

These XML products are referred to as "CatfilePlus in XML" and "Serfile in XML"

Sample NLM Data
Sample files of Catfile (in MARC 21 format only), CatfilePlus (in MARC 21 or XML format) and Serfile (in MARC 21 or XML format) are available for prospective NLM data licensees. A license agreement is not needed for sample data. For instructions on how to obtain the sample files, refer to Sample NLM Data.

How to Lease
NLM leases Catfile, CatfilePlus and Serfile to U.S. and non-U.S. individuals or organizations. There is no charge for leasing NLM data.

To request a license, complete and submit the License Request Form after reading and accepting the electronic License Agreement for NLM Data.

Alternative to Leasing
Individual records in MARC 21 format may be downloaded from LocatorPlus for personal use and a single copy of downloaded data may be redistributed. An alternative product, the List of Serials Indexed for Online Users (LSIOU), a subset of Serfile, is available in XML and PDF format. The LSIOU provides basic bibliographic information for only the serials from which articles are indexed with the MeSH® vocabulary and cited in MEDLINE (does not cover OLDMEDLINE titles). See for more information. Please note that the LSIOU uses its own DTD which is different from the DTD used for SERFILE.

Additional information
General information on the MARC 21 record structure is available from the Library of Congress at Catfile, CatfilePlus, and Serfile may be leased to non-U.S. organizations.