Contains values from a formal topical or subject classification such as the U.S. Library of Congress Subject Headings, MESH (Medical Subject Headings), CESSDA Topic Classification, etc.). Subject classifications are generally organized hierarchically and grouped by related subject matter. They may use codified identifiers (i.e. Dewey Decimal Classification). The International Code Value allows for string content which may be taken from an externally maintained controlled vocabulary (code value) including a language-location specification for the code value. Used in cases where controlled vocabularies are assumed to be highly language specific, such as nationally maintained subject headings, thesauri, or keywords derived from the content of documents.