Field definition and scope:

Field 748 contains a chronological term used as an index term that supplements terms derived from data in the MARC classification record.  The term may be referred to in the classification number and caption in field 153 (Classification Number).

The field may be used to link a classification number with a related chronological heading.  The 748 field provides access to classification numbers 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)).  The values in the second indicator position or the data in subfield $2 (Source of heading or term) identify the subject heading system or thesaurus used by an institution to formulate the chronological index term.  Index terms not controlled by a thesaurus are contained in field 753 (Index Term - Uncontrolled).

Field 748 is repeatable.

Guidelines for applying content designators:

 Field 748 parallels the 648 Subject Added Entry field in the bibliographic format.  The indicators and subfield codes below were created from the information in field 648.  Examples of field 748 are provided in this section.  Guidelines for the input conventions and the source for the content designators are in MARC 21 Format for Bibliographic Data:  648 (Subject Added Entry - Chronological Term).

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

Position

Description

Repeatability

Field 748

Index Term - Chronological

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 des 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

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

 

See:  Examples for this field.

Related MARC fields or documents:

648  Subject Added Entry - Chronological Term

MARC Code List for Organizations

Source Codes for Vocabularies, Rules, and Schemes:

Subject Heading and Term Source Codes

See also:

700-75X  Index Terms

Variable Data Fields