Library of Congress

locCreated on Aug 18th, 2020

The Library of Congress is the largest library in the world, with millions of books, recordings, photographs, newspapers, maps and manuscripts in its collections. The Library is the main research arm of the U.S. Congress and the home of the U.S. Copyright Office.

The Library of Congress occupies three buildings on Capitol Hill. The Thomas Jefferson Building (1897) is the original separate Library of Congress building. (The Library began in 1800 inside the U.S. Capitol.) The John Adams Building was built in 1938 and the James Madison Memorial Building was completed in 1981. Other facilities include the High Density Storage Facility (2002) at Fort Meade, Md., and the Packard Campus for Audio Visual Conservation (2007) in Culpeper, Va.

The Library preserves and provides access to a rich, diverse and enduring source of knowledge to inform, inspire and engage you in your intellectual and creative endeavors. Whether you are new to the Library of Congress or an experienced researcher, we have a world-class staff ready to assist you online and in person. Homepage:


Relator terms and their associated codes designate the relationship between a name and a bibliographic resource. The relator codes are three-character lowercase alphabetic strings that serve as identifiers. Either the term or the code may be used as controlled values.

Version: 2017-09-07

This document describes the MADS/RDF (Metadata Authority Description Schema in RDF) vocabulary, a data model for authority and vocabulary data used within the library and information science (LIS) community, which is inclusive of museums, archives, and other cultural institutions. It is presented as an OWL ontology.

MADS/RDF is a knowledge organization system (KOS) designed for use with controlled values for names (personal, corporate, geographic, etc.), thesauri, taxonomies, subject heading systems, and other controlled value lists. It is closely related to SKOS, the Simple Knowledge Organization System and a widely supported and adopted RDF vocabulary. Given the close relationship between the aim of MADS/RDF and the aim of SKOS, the MADS ontology has been fully mapped to SKOS.

Unlike SKOS, however, which is very broad in its application, MADS/RDF is designed specifically to support authority data as used by and needed in the LIS community and its technology systems. For example, MADS/RDF provides a means to record data from the Machine Readable Cataloging (MARC) Authorities format in RDF for use in semantic applications and Linked Data projects.

MADS/RDF is designed to support the description of cultural and bibliographic resources. Data described using MADS/RDF, therefore, assists with identifying and annotating bibliographic and cultural resources. MADS/RDF is not focused on the description of Real World Objects. Although a MADS/RDF description may contain information specific to the Real World Object associated with the MADS/RDF authoritative label, the MADS/RDF ontology distinguishes between these two entities – the RWO and the Authority.

Version: 1.4.0

Publication Frequency List is derived from a controlled list of coded values in MARC 21 Format for Bibliographic Data field 008/18.

Version: 1.0.0

BIBFRAME Vocabulary with LC Extensions

Version: 1.2.0

The BIBFRAME vocabulary uses a Linked Data model and thus leverages the RDF modeling practice of uniquely identifying as Web resources all entities, attributes, and relationships (i.e., properties) between entities. The BIBFRAME Vocabulary is comprised of the RDF properties, classes, and relationships between and among them. In addition to the basic vocabulary linked to below the extension that the Library of Congress established in its work on a BIBFRAME 2.0 pilot is specified.

Version: 2.0.1