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337 Media Type (R)

Find the field definition and scope, indicators, subfield codes, and guidelines for applying content designations for field 337.

Indicators and subfield codes

First Indicator

Sin definir

en blanco          Sin definir

Second Indicator

Sin definir

en blanco          Sin definir

Subfield Codes

‡a          Media type term (R)

‡b          Media type code (R)

‡0          Authority record control number or standard number (R)

‡1          Real World Object URI (R)

‡2          Source (NR)

‡3          Materials specified (NR)

‡8          Field link and sequence number (R)


Field definition and scope

Media type reflects the general type of intermediation device required to view, play, run, etc., the content of a resource. Used as an alternative to or in addition to the coded expression of Media type in field 007/00 (Category of material). Field 337 information enables indication of more specific media types and media types from various lists.

Multiple media types from the same source vocabulary or code list may be recorded in the same field in separate occurrences of subfield ‡a (Media type term) and subfield ‡b (Media type code). Terms from different source vocabularies are recorded in separate occurrences of the field.

Guidelines for applying content designations


Both indicators are undefined; each contains a blank (en blanco).

First Indicator - Undefined

en blanco - Undefined

Second Indicator - Undefined

en blanco - Undefined


‡a - Media type term

Subfield ‡a contains the term for the category of media used to convey the content of the resource.

337          Audio ‡2 marcmedia

‡b - Media type code

Subfield ‡b contains the code for the category of media used to convey the content of the resource.

337          ‡b n ‡2 marcmedia ‡3 liner notes

‡0 - Authority record control number or standard number

Subfield ‡0 contains the system control number of the related authority record, or a standard identifier such as an International Standard Name Identifier (ISNI). The control number or identifier is preceded by the appropriate MARC Organization code (for a related authority record) or the Standard Identifier source code (for a standard identifier scheme), enclosed in parentheses. In the latter case, the parenthetical "(uri)" is redundant and should not be included if the identifier is given in the form of a Web retrieval protocol, e.g., HTTP URI, which is self-identifying.

See MARC Code List for Organizations ( for a listing of organization codes and Standard Identifier Source Codes ( for code systems for standard identifiers. Subfield ‡0 is repeatable for different control numbers or identifiers. Subfield ‡0 is to be used for recording URIs which represent objects in RDF triple statements.

‡1 - Real World Object URI

Subfield ‡1 contains a URI that identifies a description of an entity, sometimes referred to as a Thing, a Real World Object, or RWO, whether actual or conceptual. When dereferenced, the URI points to a description of that entity. A URI that identifies a name or label for an entity is contained in subfield ‡0.

‡2 - Source

Subfield ‡2 contains the MARC code that identifies the source of the number or code used to record the media type information. Code from: Genre/Form Code and Term Source Codes.

‡3 - Materials specified

Subfield ‡3 contains information that indicates the part of the described material to which the field applies.

‡8 - Field link and sequence number

Subfield ‡8 contains data that identifies linked fields and may also propose a sequence for the linked fields. Subfield ‡8 may be repeated to link a field to more than one other group of fields.

The structure and syntax for the field link and sequence number subfield is: ‡8<linking number>.<sequence number>\<field link type>

The linking number is the first data element in the subfield and required if the subfield is used. It is a variable-length whole number that occurs in subfield ‡8 in all fields that are to be linked. Fields with the same linking number are considered linked. A linking number of "0" (zero) is not used in this field.

The sequence number is separated from the linking number by a period "." and may be optional. It is a variable-length whole number that may be used to indicate the relative order for display of the linked fields (lower sequence numbers displaying before higher ones).

The field link type is separated from preceding data by a reverse slash "\". It is a code indicating the reason for the link and it follows the link number or sequence number if present. The following one-character field link type code has been defined for use in subfield 8 in OCLC local holdings records: a - Action

Code a is used in a record to link one or more fields with another field to which the processing or reference actions relate. This code is typically used only when there is more than one 5XX that relates to another 5XX field.

541          ‡8 1.1\a ‡3 Public School and College Authority and Trade School and Junior College Authority project files ‡a Finance Dept ‡c
                Transferred ‡u

583          ‡8 1.2\a ‡a Appraised ‡c 198712- ‡l tjb/prr

583          ‡8 1.3\a ‡a Scheduled ‡c 19880127 ‡k mc/dmj

583          ‡8 1.4\a ‡a Arranged ‡c 19900619 ‡k mc/dmj

583          ‡8 1.2\a ‡a Processed level 2 ‡b 90.160 ‡c 9901218 ‡k kmc/dmj