Field definition and scope:

Field 648 contains a chronological term used as a subject added entry.

Subject added entries are assigned to a community information record to provide access according to generally accepted thesaurus-building rules (e.g., Library of Congress Subject Headings (LCSH), Medical Subject Headings (MeSH), Faceted Application of Subject Terminology (FAST)).  Field 648 may be used by any institution assigning subject headings based on the lists and authority files identified in the second indicator position or in subfield $2 (Source of heading or term).

Field 648 is repeatable.

Guidelines for applying content designators:

The content designators identify the subelements occurring in chronological terms and subdivisions.

For indicator and subfield code definitions and examples, and designator repeatability, see table below:

Position

Description

Repeatability

Field 648

Subject Added Entry - Chronological Term

R

Indicator:

 

 

First

Undefined; contains a blank

 

 

 

 

Second

Thesaurus

 

0

Library of Congress Subject Headings

 

1

LC subject headings for children's literature

 

2

Medical Subject Headings

 

3

National Agricultural Library subject authority file

 

4

Source not specified

 

5

Canadian Subject Headings

 

6

Répertoire de vedettes-matière

 

7

Source specified in subfield $2

 

 

 

 

Subfield code:

 

 

$a

Chronological term

NR

$v

Form subdivision

R

$x

General subdivision

R

$y

Chronological subdivision

R

$z

Geographic subdivision

R

$0

Authority record control number

R

$2

Source of heading or term

NR

$3

Materials specified

NR

$6

Linkage

NR

$8

Field link and sequence number

R

Input conventions:

Display constant

Content designator history:

Subfield $0 - Authority record control number  [new, 2007]

Related MARC fields or documents:

880  Alternate Graphic Representation

Source Codes for Vocabularies, Rules, and Schemes:

Subject Heading and Term Source Codes

See also:

6XX  Subject Access Fields

Variable Data Fields