Field definition and scope:

Field 748 contains a chronological term that is equivalent to the 148 chronological term or 182 chronological subdivision heading field of the same record.  It links headings within a system or from different thesauri or authority files.

The National level record requirement for this field is Optional.

Field 748 is repeatable.

Guidelines for applying content designators:

The content designators identify the subelements occurring in chronological term headings constructed according to generally accepted thesaurus-building conventions (e.g., Faceted Application of Subject Terminology (FAST)).

Chronological terms include dates that are used as the lead element of subject or added entry access fields in bibliographic records.

A chronological term that is authorized for use only as a subject subdivision part of an extended subject heading is contained in a 182 (Chronological Subdivision) field.

For indicator and subfield code definitions and examples, National level (NLR) record requirements, and designator repeatability, see table below:

Position

Description

NLR

Repeatability

Field 748

Established Heading Linking Entry - Chronological Term

O

R

Indicator:

 

 

 

First

Undefined; contains a blank

M

 

 

 

 

 

Second

Thesaurus

M

 

0

Library of Congress Subject Headings/Name authority file

A

 

1

LC subject headings for children's literature

A

 

2

Medical Subject Headings/NLM name authority file

A

 

3

National Agricultural Library subject authority file

A

 

4

Source not specified

A

 

5

Canadian Subject Headings/LAC name authority file

A

 

6

Répertoire de vedettes-matière

A

 

7

Source specified in subfield $2

A

 

 

 

 

 

Subfield code:

 

 

 

$a

Chronological term

M

NR

$i

Relationship information

A

R

$v

Form subdivision

A

R

$w

Control subfield

A

NR

 

/0  Link display

M

 

 

/1  Replacement complexity

A

 

$x

General subdivision

A

R

$y

Chronological subdivision

A

R

$z

Geographic subdivision

A

R

$0

Authority record control number or standard number

A

R

$2

Source of heading or term

A

NR

$4

Relationship

O

R

$5

Institution to which field applies

A

R

$6

Linkage

A

NR

$8

Field link and sequence number

O

R

 

See:  Examples for this field.

Input conventions:

Punctuation

Spacing

Order of subfields

Relationship codes

Display constant for X48 fields

Display constants for 7XX Linking Entries

Content designator history:

748 - Established Heading Linking Entry - Chronological Term  [new, 2002]

Subfield $i - Relationship information  [new, 2014]

Subfield $0 - Record control number  [redefined, 2010]

Subfield $w/1 - Replacement complexity  [new, 2002]:  In 2002, subfield $w/1 was defined with the following codes:  a (Heading replacement does not require review); b (Heading replacement requires review); and n (Not applicable).

Subfield $4 - Relationship code  [new, 2014]

Subfield $4 - Relationship code  [renamed, 2017] [redescribed, 2017]:  Subfield $4 was renamed to Relationship and redescribed to allow for the recording of relationship URIs in addition to MARC and non-MARC codes.

LC Guidelines:

 748  Established Heading Linking Entry - Chronological Term

DCM Z1 Instructions:

 7XX  Heading Linking Entries

Related MARC fields or documents:

X48  Chronological Terms - General Information

7XX  Heading Linking Entries - General Information

RDA in MARC Authority Data

Source Codes for Vocabularies, Rules, and Schemes:

Subject Heading and Term Source Codes

See also:

7XX  Heading Linking Entries

Variable Data Fields