MARC 21 Format for Bibliographic Data: 76X-78X: Linking Entries-General Information (Network Development and MARC Standards Office, Library of Congress)

Information that identifies other related bibliographic items. Each of the linking entry fields specifies a different relationship between the target item described by the record and a related item. These relationships fall into three classes: 1) related items that assist the user in continuing to search but are not physically required to obtain the target item (e.g., former entries for continuing resources, translations of the target item); 2) related items that have to be obtained physically in order to use the target item (e.g., the host item for a component part: a journal issue containing a specific article); 3) related items that are constituent units of a larger whole (e.g., the individual photographs contained in a visual material collection). The linking entry fields are designed to generate a note in a display of the record in which they appear. They can also provide machine linkage between the bibliographic record for the target item and the bibliographic record for the related item, if the related item is covered by a separate record; and/or facilitate indexing.

TERMS USED IN LINKING ENTRY FIELDS

Target Item - Bibliographic item that is the principal or primary unit covered by the description for which the record was constructed. The target item is the item to which the information in character positions 06 (Type of record) and 07 (Bibliographic level) of the Leader, and field 245 (Title Statement) apply.

Related Item - Bibliographic item that has a chronological, horizontal (different versions), or vertical (hierarchical) relationship with a target item, and for which the linking entry field is formulated.

Component Part - Bibliographic item that is physically part of another bibliographic item such that the retrieval of the part is dependent on the physical identification and location of the host item (e.g., a chapter in a book, an article in a journal). (Field 774)

Constituent Unit - Bibliographic item that is part of another item. The constituent unit is physically separate from the item of which it is considered a part. (Fields 770, 774)

Host Item - Bibliographic item that either physically contains (as in the case of the component part), or bibliographically includes (as in the case of a constituent unit), the subpart that is the target item for the record. For example, if a record describes a journal article, the host is the journal; if a record describes one digital item in a set, the host is the set. (Fields 772, 773)

Chronological Relationship - Relationship in time between bibliographic items (e.g., the relation of a serial to its predecessors and successors). (Fields 777, 780, 785)

Horizontal Relationship - Relationship between versions of a bibliographic item in different languages, formats, media, etc. (Fields 765, 767, 775, 776)

Vertical Relationship - Hierarchical relationship of the whole to its parts and the parts to the whole (e.g., a journal article to the journal, collective title of conference proceedings to individual titles of contributions, subseries to main entry series). (Fields 760, 762, 770)

RECORD LINKS AND NOTES

Linking Entry Fields (fields 760-787) - Fields carry descriptive data concerning the related item, the control number for the record of the related item, or both. Minimal content designation is provided for the data concerning the related item that is used in the linking entry fields. For data operations requiring fuller content designation such as indexing and sorting, subfield $w (control number for the related item) allows the system to follow that link to the related record to obtain fully content-designated data. Moreover, the coded data in control subfield $7 allows some types of indexing without reference to the actual related record. The value used in the first indicator position of a linking entry field determines whether a note is to be generated from the linking entry field or from field 580.

In fields 76X-78X the general resource to resource relationship is indicated by the choice of tag with some more specific relationships indicated by indicators in fields 772, 780, and 785. Subfield $i is used to indicate relationships not expressed in the tag or indicator, thus is appropriate for more specific relationship designations. If it is desirable to make the specific relationship information available in a coded form, subfield $4 is used.

Linking Entry Complexity Note (field 580) - Linking Entry Fields are designed to support generation of a note concerning the related item in a display of the record for the target item. When the relationship is too complex to be expressed using relationship information expressed by the tag indicator, or $i or $4 subfields, and the data from the linking entry field or the linked record, the note is recorded in the Linking Entry Complexity Note field. When used, this field appears in addition to any relevant 760-787 linking entry field, and no note is generated from the linking entry field.

Added Entries (fields 700-730) - When an added entry is desired for a title used in a linking field, the added entry is recorded in the appropriate 700-730 field. Linking fields are not intended to take the place of added entries. Likewise, an added entry in field 700-730 does not take the place of a linking field, as it cannot cause a note to be generated or carry a record link.

Component Parts/Constituent Units - Linking entry field 773 (Host Item Entry) is used to link the record for a component part that is an integral part of another item to the record for the other item. For example, in records for journal articles, it contains an identification of the journal. The exact location of the article in the journal is recorded in subfield $g of field 773. The record for the host item or any larger bibliographic unit may include information about constituent units, recorded in the repeatable field 774 (Constituent Unit Entry). Information about each constituent would be recorded in a separate occurrence of field 774.

GUIDELINES FOR APPLYING CONTENT DESIGNATORS

■ INDICATORS

First Indicator - Note controller

Whether or not a display note is to be generated from the field.

0 - Display note

Note is to be generated from the data in the linking entry field (or from the related record identified in the field).


780	00$tAmerican journal of religious psychology and education

1 - Do not display note

Note is not to be generated from the data in the linking entry field (or from the related record). Value 1 is used when the display constant associated with the linking field does not adequately describe the relationship. In this case, a note for display is recorded in field 580. The 760-787 field is recorded to provide the machine linkage and field 580 is used for display.

■ SUBFIELD CODES

As a general rule, each subfield defined for the linking entry fields corresponds to a field or field block that would be used to describe the related item in a separate record. A separate bibliographic record for the related item may or may not exist. For example, subfield $a (Main entry heading), corresponds to the 1XX (Main Entries) block; subfield $t (Title) corresponds to field 245 (Title Statement), and so on. The rules and practices applied to formulating the data in the linking entry fields are usually the same as would be followed for formulating the data about a related item in a separate bibliographic record except that the information provided need not be as complete. The fullness of the bibliographic information about the related item recorded in the linking entry fields should be based on the intended use of the links. When the related item is represented by a separate bibliographic record, recording only the basic bibliographic details (e.g., title, and relationship information) is usually sufficient.

$a - Main entry heading

Main entry heading data (without the content designators) from field 100 (Main Entry-Personal Name), 110 (Main Entry-Corporate Name), or 111 (Main Entry-Meeting Name) in the related record. Individual components of the name or uniform title are not recorded in a separate subfield as they would be in a 1XX field.


	Related record:
100	1#$aMellor, Alec.
245	10$aStrange masonic stories
	Linking entry:
775	0#$aMellor, Alec.$tStrange masonic stories$eeng

$b - Edition

Name of the edition from field 250 (Edition Statement) of the related record.


	Related record:
245	04$aThe Wall Street journal.
250	##$aSouthwest ed.
	Linking entry:
775	0#$tWall Street journal$bSouthwest ed.

$c - Qualifying information [all except 773]

Data needed to distinguish between two titles. This information is generally parenthetical information supplied by the cataloger. In pre-AACR 2 records for serials, subfield $c contains the information usually taken from subfield $b (Qualifying information) of field 222 (Key Title).

$d - Place, publisher, and date of publication

Publication information from subfields $a, $b, and/or $c of field 260 (Publication, Distribution, etc. (Imprint)) of the related record.

$e - Language code [775 only]

Language code from field 008/35-37 (Language) of the related record.


	Related record:
008/35-37	fre
	Linking entry:
775	1#$tDiscours du budget$efre

$f - Country code [775 only]

Country code from field 008/15-17 (Place of publication, production, or execution) of the related record.

$g - Related parts

Data that indicates the specific piece or pieces of the related item that are involved in the relationship with the resource described in the 1XX/245 of the record, such as dates and volumes. The related parts information includes the location of a component part in a target item.


772	1#$tDevelopmental biology$x0012-1606$g1972-1974
773	0#$tHorizon$gVol. 17, no. 98 (Feb. 1948), p. 78-159

$h - Physical description

Physical description of the related item.

$i - Relationship information

Designation of a relationship between the resource described in the 76X-78X field and the resource described in the 1XX/245 of the record. This may be in the form of uncontrolled text or a controlled text value. The second indicator contains value 8 (No display constant generated) except in fields 780 and 785 when data in this subfield is intended to be displayed. The data in subfield $i can be displayed preceding the other data contained in the field.


100	1# $aVerdi, Giuseppe, $d1813-1901.
245	10 $aOtello :$bin full score /$cGiuseppe Verdi.
700	1# $iLibretto based on (work) $aShakespeare, William, $d1564-1616. $tOthello.
787	08 $ireproduction of (manifestation) $aVerdi, Giuseppe, $d1813-1901. $tOtello.$d Milan: Ricordi, c1913

User display:
Verdi, Giuseppe, $d 1813-1901. Otello : in full score / Giuseppe Verdi
	Reproduction of Verdi, Giuseppe, 1813-1901. Otello. Milan : Ricordi, c1913 Libretto based on Shakespeare, William, $d 1564-1616. Othello.


245	00 136th Street, southeastern section of the Bronx.
300	## $a 11 slides.
774	08 $iComponent item:$o NYDA.1993.010.00132.$n[DIAPimage]. $tView SE from Mill Brook Houses on rooftop on Cypress Ave. Between 136th St. and 137th St.,$d93/05

$j - Period of content [786 only]

Beginning, and if appropriate, the ending date(s) of the content of the related item. The information is recorded according to Representation of dates and times (ISO 8601). The date requires 8 numeric characters in the pattern yyyymmdd (4 for the year, 2 for the month, and 2 for the day). The time requires 8 numeric characters in the pattern hhmmss.f (2 for the hour, 2 for the minute, 2 for the second, and 2 for a decimal fraction of the second, including the decimal point). The 24-hour clock (00-23) is used. An indication of the basis on which the source time period of content information was determined is also recorded in this subfield.

$k - Series data for related item [all except 760 and 762]

Series entry from the 4XX (Series Statement) or 8XX (Series Added Entry) of the related record. Note: The parentheses that enclose the series statement are not carried in the MARC record. They may be system generated as display constants associated with the presence of subfield $k.

$m - Material specific details

Material specific information (e.g., for maps, the mathematical data information relating to the related item).

$n - Note

Note about the related bibliographic item.

$o - Other item identifier

Numbers, codes, etc. used to identify an item when these identifiers are not appropriate for one of the more specific subfields (e.g., subfield $z (ISBN)). Examples include item or accession numbers.


774	00$oNYDA.1993.010.00132$n[DIAPimage].$tView SE from Mill Brook Houses on rooftop on Cypress Ave. between 136th St. and 137th St.,$d93/05

$p - Abbreviated title [773 and 786 only]

Abbreviated title from field 210 (Abbreviated Title) of the related record.

$q - Enumeration and first page [773 only]

Enumeration and pagination designations that are formed using the rules for the creation of the Enumeration and Location segments of the SICI (Serial Item and Contribution Identifier). These provide reference to the enumeration and first page data elements for the constituent unit of the host item described in the 773 field.


773	0#$7nnas$tCalifornia journal.$gVol. 24, pt. B no. 9 (Sept. 1993), p. 235-48$q24:B:9<235

$r - Report number [all except 760, 762, and 777]

Report number from field 088 (Report Number) of the related record.

$s - Uniform title

Title from field 240 (Uniform Title) or field 243 (Collective Uniform Title) of the related record. When subfield $s is used in a linking field for related legal materials or translations, subfield $t is usually also included in the linking field.

$t - Title

Title information from subfields $a, $f, $g, $k, $n, and $p of fields 130 (Main Entry - Uniform Title) and 245 (Title Statement) of the related record. Individual components of the title are not separately subfield coded. (Prior to 1981, subfield $t was sometimes derived from subfield $a of field 222 (Key Title) when the key title was present on the record.)


	Related record:
245	00$aArmy, Navy, Air Force register.
580	##$aMerged with: Army, Navy, Air Force journal, to form ...
	Linking entry:
785	17$tArmy, Navy, Air Force journal

$u - Standard Technical Report Number [all except 760, 762, and 777]

Standard Technical Report Number from field 027 (Standard Technical Report Number) of the related record. Note: The initialism STRN: that precedes the number is not carried in the MARC record. It may be system generated as a display constant associated with the presence of subfield $u.

$v - Source contribution [786 only]

Brief statement identifying the information contributed by a source to a data set. It is used primarily with linking field 786 (Data Source Entry).


786	0#$aDefense Mapping Agency.$tReno, NV-CA west digital terrain elevation data$vData for reformatting to DEM format

$w - Record control number

System control number of the related record preceded by the MARC code, enclosed in parentheses, for the agency to which the control number applies. See Appendix I: Organization Code Sources for a listing of sources used in MARC 21 records.


780	00$tTechniques of biochemical and biophysical morphology$w(DLC)###72000153#$w(OCoLC)1021945
780	00$tReview of existential psychology & psychiatry$w(DLC)sf#77000170#
785	17$tAdult correctional services in Canada$w(CaOONL)840790694E

$x - International Standard Serial Number

ISSN for a serial title from field 022 (International Standard Serial Number) in the related record. (The ISSN is an agency-assigned data element. ISSN's are assigned to serial publications by national centers under the auspices of the ISSN Network.) Note: The initialism ISSN that precedes the number is not carried in the MARC record. It may be system generated as a display constant associated with the presence of subfield $x.


245	00$aAnnual law review /$cUniversity of Western Australia.
785	00$tUniversity of Western Australia law review$x0042-0328$w(OCoLC)1587621

$y - CODEN designation

CODEN designation, a unique identifier for scientific and technical periodical titles, from field 030 (CODEN Designation) in the related record. Note: The acronym CODEN that precedes the number is not carried in the MARC record. It may be system generated as a display constant associated with the presence of subfield $y.


780	00$tIllinois journal of mathematics$yIJMTAW$w(DLC)###59003745#

$z - International Standard Book Number [all except 760, 762, and 777]

ISBN from field 020 (International Standard Book Number) in the related record. (The ISBN is an agency-assigned data element.) Note: The initialism ISBN that precedes the number is not carried in the MARC record. It may be system generated as a display constant associated with the presence of subfield $z.

$3 - Materials specified [773 only]

Part of the described materials to which the field applies.

$4 - Relationship code

Designation in coded form of a relationship between the resource described in the 76X-78X field and the resource described in the 1XX/245 of the record.

$6 - Linkage

See description of this subfield in Appendix A: Control Subfields.

$7 - Control subfield

Up to four character positions (designated 0, 1, etc.) that indicate special characteristics of the linked entry. Because the definitions of the codes in subfield $7 are dependent on the character position in which they occur, the coding of any character position mandates that each preceding character position contains a code or the fill character (|); succeeding character positions need not be used. For example, if position 0 and 1 are not applicable but position 2 is applicable, then position 0 and 1 contain code n (Not applicable) or a fill character.

/0 - Type of main entry heading

Code indicating either the type of name contained in subfield $a or the uniform title in subfield $t. The codes correspond to the 1XX tag in the record for the related item: 100 (Main Entry-Personal Name), 110 (Main Entry-Corporate Name), 111 (Main Entry-Meeting Name), and 130 (Main Entry-Uniform Title). Code n is used when no other codes apply.

p	Personal name
c	Corporate name
m	Meeting name
u	Uniform title
n	Not applicable

/1 - Form of name

Code indicating the form of the name contained in subfield $a. The code corresponds to the value of the first indicator in the 1XX field in the record for the related item, and must thus be interpreted in conjunction with the value in position 0.If position 0 = p (Personal name), position 1 contains one of the following codes:

0	Forename
1	Surname
3	Family name

If position 0 = c (Corporate name) or m (Meeting name), position 1 contains one of the following codes:

0	Inverted name
1	Jurisdiction name
2	Name in direct order

If position 0 = u (Uniform title) or n (Not applicable), position 1 contains:

n	Not applicable

/2 - Type of record

Code indicating the type of record for the related item. The code corresponds to the code in Leader/06 (Type of record) in the record for the related item.

a	Language material
c	Notated music
d	Manuscript notated music
e	Cartographic material
f	Manuscript cartographic material
g	Projected medium
i	Nonmusical sound recording
j	Musical sound recording
k	Two-dimensional nonprojectable graphic
m	Computer file
o	Kit
p	Mixed material
r	Three-dimensional artifact or naturally occurring object
t	Manuscript language material

/3 - Bibliographic level from Leader/07 of related record

Code indicating the bibliographic level of the related item. The code corresponds to that in Leader/07 in the record for the related item.

a	Monographic component part
b	Serial component part
c	Collection
d	Subunit
i	Integrating resource
m	Monograph/item
s	Serial


772	1#$7unas$tPost boy (London, England)
773	0#$7p1am$aDesio, Ardito, 1897-$tGeographical features of the Karakorum.$dMilano : ISMEO, 1991

$8 - Field link and sequence number

See description of this subfield in Appendix A: Control Subfields.

INPUT CONVENTIONS

Establishing a link - Links are established reciprocally in related bibliographic records. A linking entry field links to a related item which may be represented in a file by a record. When related records exist, each record may contain a corresponding linking entry. In some cases the reciprocal linking entries use the same field tags, in others they have corresponding field tags. The reciprocal field tags are as shown below:

Record	Related record
760 (Main Series Entry)	762 (Subseries Entry)
765 (Original Language Entry)	767 (Translation Entry)
770 (Supplement/Spec. Issue Entry)	772 (Supplement Parent Entry)
773 (Host Item Entry)	774 (Constituent Unit Entry)
775 (Other Edition)	775 (Other Edition)
776 (Additional Physical Form)	776 (Additional Physical Form)
777 (Issued With Entry)	777 (Issued With Entry)
780 (Preceding Entry)	785 (Succeeding Entry)
787 (Nonspec. Relationship Entry)	787 (Nonspec. Relationship Entry)

Definitions of the second indicator values for reciprocal fields 780 and 785 are also reciprocal as shown below:

2nd indicator of 780	2nd indicator of 785
0-Continues	0-Continued by
1-Continues in part	1-Continued in part by
2-Supersedes	2-Superseded by
3-Supersedes in part	3-Superseded in part by
4-Formed by union of... and...	7-Merged with... to form...
5-Absorbed	4-Absorbed by
6-Absorbed in part	5-Absorbed in part by
7-Separated from	6-Split into... and...
------	8-Changed back to...

Initial articles - Initial articles in the entry of the related record are omitted in linking entry fields except in entries where the intent is to file on the initial article.


	Related record:
245	04$aThe Journal of microbiology.
	Linking entry:
780	00$tJournal of microbiology


	Related record:
110	1#$aEl Salvador.$bDirección General de Estadística.
245	10$aResúmen estadístico de la República de El Salvador.
	Linking entry:
780	01$aEl Salvador. Dirección General de Estadística.$tResúmen estadístico de la República de El Salvador

CONTENT DESIGNATOR HISTORY

Fields 760-787 originally were defined only in the serials specifications and contained information describing relationships between bibliographic items that did not necessarily facilitate indexing or provide a machine link to the record for the related item. In 1977, subfield $w (Record control number) was defined in these fields to facilitate linkage among records within a given system and across systems.

In 1981, the following fields were validated for the books specifications and subfield $r was defined to permit linkage through report numbers of technical report materials: 765, 767, 770, 772, 775, 776, 780, 785, and 787.

When the record-linking technique was fully developed in 1982, field 773 (Host Item Entry) was defined for all MARC specifications to accommodate the cataloging of component parts. The definitions of several other subfields were either broadened or more narrowly defined at that time.

Field 786 - Data Source Entry [NEW, 1995]
Field 787 - Nonspecific Relationship Entry [RENAMED, 2009]

$c - Place of publication (SE) [REDEFINED, 1976]
$d - Dates of publication (SE) [OBSOLETE, 1976]
$g - Relationship dates [REDEFINED, 1982]
Subfield $g was broadened in 1982 as part of the record-linking specifications, specifically to include the location information of a component part in a host item.
$b - Edition [NEW, 1982]
$d - Place, publisher, and date of publication [NEW, 1982]
$g - Relationship information [RENAMED, 2009]
$i - Display text [REDEFINED, 2009]
$k - Series data for related item [NEW, 1982]
$s - Uniform title [NEW, 1982]
$q - Parallel title [OBSOLETE, 1990]
$q - Enumeration and first page [NEW, 2003]
$7 - Control subfield [NEW, 1982]
Prior to 1982, edition statements and publication statements were recorded in subfield $c, and uniform titles were recorded in subfield $t.
$7/1 - Form of name2 - Multiple surname [OBSOLETE, 1996]
Use of the Form of name code 2 (Multiple surname) was made obsolete when code 1 (Single surname) was redefined as surname to be used for headings with either single or multiple surnames.
$7/2 - Type of record
$b - Archival and manuscripts control [OBSOLETE, 1995]
$7/3 - Bibliographic level from Leader/07 of related record
p - Pamphlet [OBSOLETE] [CAN/MARC only]

$4 - Relationship code [NEW, 2009]

76X-78X - Linking Entries-General Information

DEFINITION AND SCOPE