Library of Congress

Authorities & Vocabularies

The Library of Congress > Linked Data Service

Small Datasets

The Linked Data Service is to provide access to commonly found standards and vocabularies promulgated by the Library of Congress. This includes data values and the controlled vocabularies that house them. Below are descriptions of various codelists and schemas from the MARC documentationOffsite link standard. Inside each, a search box allows you to search the vocabularies individually .

Standard Identifiers

Standard Identifiers Scheme lists standard number or code systems and assigns a URI to each database or publication that defines or contains the identifiers. The purpose of these source codes is to enable the type of standard numbers or codes in resource descriptions to be indicated by URI.



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Carriers

Carriers Scheme is derived from a controlled list of values representing the format of the storage medium and its media type, which is principally used in RDA cataloging.



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Content Types

Content Types Scheme is derived from a controlled list of values representing the form of communication through which a work is expressed, which is principally used in RDA cataloging.



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Media Types

Media Types Scheme is derived from a controlled list of values reflecting the general type of intermediation device required to view, play, run, etc., the content of a resource, which is principally used in RDA cataloging.



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Resource Types

Resource Types Scheme is derived from a controlled list of coded values in MARC 21 Format for Bibliographic Data. It is used also in MODS. It has been augmented with types beyond those specified in MARC and MODS/XML.



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MARC List of Genre/Form Schemes

Genre/Form Schemes contains a list of genre/form schemes and assigns a URI to each scheme. The purpose of these properties is to permit users to associate controlled genre/form term with the appropriate scheme.

The schemes include lists that contain the following types of information:

  • content types that indicate the form of communication through which a work is expressed. Examples include: cartographic dataset, notated music, or text.
  • media types that specify the general type of intermediation device required to view, play, run, etc., the content of a resource audio, stereographic, or video.
  • carrier types that specify the format of the storage medium and housing of a resource. Examples include audiocassette, microfiche, or online resource.
  • genre types designate the style or technique of the intellectual content of textual materials or, for graphic materials, aspects such as vantage point, intended purpose, characteristics of the creator, publication status, or method of representation. Examples are: biographies, catechisms, essays, hymns, or reviews.
  • form and physical characteristic types designate historically and functionally specific kinds of materials distinguished by their physical character, the subject of their intellectual content, or the order of information within them. Examples are: daybooks, diaries, directories, journals, memoranda, questionnaires, syllabi, or time sheets.

The purpose of this list is to identify the vocabulary used in records. For code assignment, general structure, usage, and maintenance guidelines see Source Codes for Vocabularies, Rules, and Schemes .

Many general subject lists and thesauri, such as the Library of Congress Subject Headings and the Art and Architecture Thesaurus, also contain controlled vocabularies for specifying genre/forms. Thus those general sources may also be used in usage elements identified for genre/form terms, with the appropriate source code (see Subject Schemes) . Only sources that are specific for genre/form are listed here.

Entries in the list are arranged in alphabetical order by the code and consist of the source code followed by the bibliographic citation for the source documentation. The citations are linked to the online source for some codes.

Each code consists of a maximum of 12 lowercase alphabetic characters. Possible additions to codes are described in Source Codes .



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MARC List of Subject Schemes

Subject Schemes contains a list of subject schemes and assigns a URI to each scheme. The purpose of these properties is to permit users to associate controlled subjects with the appropriate subject scheme.

These schemes are general subject heading and thesauri, such as the Library of Congress Subject Headings, along with a number of focused subject term lists like Medical Subject Headings or Getty Thesaurus of Geographic Names. Additional specialized lists are provided with source codes in

Since general thesauri often contain a broad spectrum of terms, including genre, forms, occupations, functions, and time periods, the source codes in this list may be used in the metadata elements identified for each of the specialized source lists.

Some subject heading lists incorporate names and titles and others employ independent name and title lists for parts of a subject heading. Thus the lists assigned source codes in Name and Title Source Codes may also be used in the metadata elements identified.

Classification schemes and subject category codes include caption terms and, frequently, index terms that identify the classes in the scheme and the category codes. Some systems use those caption and index terms as subject terms in bibliographic data. Thus the lists assigned source codes in Classification Schemes and Subject Category Code Source Codes may also be used in the metadata elements identified, when the terms from those classification schemes and subject category codes are used as subject terms.

Entries in the list may include the bibliographic citation for the source documentation. The citations are linked to the online source for some codes. In some cases those citation links are RDF resources.

Each code consists of a maximum of 12 lowercase alphabetic characters. Possible additions to codes are described in Source Codes .



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List of Classification Schemes

Classification Schemes contains a list of classification schemes and assigns a URI to each scheme. The purpose of these properties is to permit users to associate classification numbers with the appropriate classification scheme.

An individual URI has been assigned for each edition of Dewey.



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List of Description Convention

Description Conventions is a vocabulary that provides URIs for standard rules or guidelines for describing bibliographic resources, commonly called cataloging rules.



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List of Publication Frequencies

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



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List of Resource Components

Resource Component List is derived from a controlled list of subfield values in MARC 21 Format for Bibliographic Data field 041.



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Library of Congress BIBFRAME Ontology

Initiated by the Library of Congress, BIBFRAME provides a foundation for the future of bibliographic description, both on the web, and in the broader networked world. This site presents general information about the project, including presentations, FAQs, and links to working documents. In addition to being a replacement for MARC, BIBFRAME serves as a general model for expressing and connecting bibliographic data. A major focus of the initiative will be to determine a transition path for the MARC 21 formats while preserving a robust data exchange that has supported resource sharing and cataloging cost savings in recent decades.



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