PROPOSAL NO. 95-2

DATE: Dec. 2, 1994
REVISED:

NAME: Definition of Subfield $v for Form Subdivision in the USMARC Formats

SOURCE: ALA/ALCTS Subject Analysis Committee

SUMMARY: This paper proposes a new subfield $v for form subdivisions in fields 6XX and 755 in the bibliographic format, 1XX, 4XX, and 5XX in the authority format, 75X in the classification format, and 6XX in the community information format and new fields 183, 483, 583, and 783 for subdivision headings in the authority format. It reviews the desirability for such a subfield and discusses technical issues involved in implementing such a change. It poses questions on retrospective conversion, issues of authority control and implementation options.

KEYWORDS: Subfield $v (Bibliographic/Authority/Classification/ Community Information); Form Subdivisions; Field 183 (Authority); Field 483 (Authority); Field 583 (Authority); Field 783 (Authority)

RELATED: DP79 (June 1994); DP74 (February 1994)

STATUS/COMMENTS:

12/2/94 - Forwarded to USMARC Advisory Group for discussion at the February 1995 MARBI meetings.

2/16/95 - Results of USMARC Advisory Group discussion - Approved as amended.

The description of subfield $k (Form subheading) needs to be changed so that there is not confusion with subfield $v. The field tag should be changed to 185, 485, 585, 785 in the authority format for Form subdivision. Examples need to be added for thesauri other than LCSH (MeSH, AAT). With the approval of this proposal, thesauri other than LCSH can begin to use subfield $v.

LC was encouraged to develop a plan for implementation for LCSH. Discussion indicated that to do so LC will need to consider the following issues:

2/16/95 - Results of final LC review - Agreed with the MARBI decisions.


PROPOSAL NO. 95-2: Definition of Subfield $v for Form Subdivision

1.       BACKGROUND

The Subject Subdivisions Conference was sponsored by the Library of
Congress and held in May 1991 at Airlie House in Virginia to
address subdivision practice in the Library of Congress subject
headings system.  Its purpose was to make the assignment of subject
headings more efficient, to enhance and encourage cooperative
cataloging efforts, and to improve subject access for online public
access catalog users.  Six recommendations resulted. 
Recommendation No. 4 suggested the addition of a separate subfield
code for form subdivisions in subject heading fields of the USMARC
bibliographic and authority formats.  It stated:

         "4. The question of whether subdivisions should be coded
         specifically to improve online displays for end users should
         be considered by organizations such as the Network Development
         and MARC Standards Office at the Library of Congress, MARBI,
         the Subject Analysis Committee (SAC) of the American Library
         Association, and the utilities, among others.  In particular,
         the Library of Congress should investigate implementing a
         separate subfield code for form subdivisions."

As a follow-up to this recommendation, the ALA SAC Subcommittee on
Nature and Use of Form Data formally submitted a request to the
Network Development and MARC Standards Office to add a separate
repeatable subfield code for form subdivisions, so that they can be
distinguished from topical, geographic, and chronological
subdivisions.  

Currently form subdivisions are put into subfield $x (General
subdivision), although there are specific subfields for
chronological ($y) and geographic ($z) subdivisions.  Fields that
would need this new subfield would be: 6XX (Subject Access fields),
755 (Added Entry--Physical Characteristics) in the bibliographic
format (see Discussion Paper No. 82: Merging Field 755 with Field
655) considering the issue of making this field obsolete; 1XX
(Headings), 4XX (See From Tracing fields), 5XX (See Also From
Tracing fields) in the authority format; 75X (Index Term fields) in
the classification format; and 6XX (Subject Access fields) in the
community information format.  If a new subfield code were defined
for form subdivisions, then new fields would also be needed for
form subdivision headings in the following areas:  18X (Heading),
48X (See From Tracing), 58X (See Also From Tracing), and 78X
(Subdivision Linking Entry), as these fields exist for other types
of subdivisions.

Discussion Paper No. 79 was discussed at the June 1994 meetings of
the USMARC Advisory Group.  This paper explored the implications
for existing records and urged institutions to consider the amount
of resources that might be required to implement.  It was suggested
that LC could choose not to implement, but others should have the
benefit of being able to use a subfield specifically for form
subdivisions.  However, it is not clear that it would be desirable
or even possible for a new subfield for form to be defined in the
USMARC standard without LC using it, particularly since LC is the
major originator of subject authority records for LCSH.  

The discussion resulted in a request that LC prepare a proposal to
define subfield $v in the Bibliographic 6XX fields with
accompanying additions to Authority 1XX fields.  In addition, an
Authority 18X subdivision field would be needed.  Participants
suggested that consideration be given to a proposal to include a
new field 155 in the Authority format complementary to field 655
(Index Term--Genre/Form).  It was also requested that LCSH plans
for using the new subfield be stated in the proposal, especially in
terms of use of field 655.  In order for the impact of such a major
change to be assessed, a questionnaire was distributed on the
USMARC discussion list.  A MARBI member is compiling the results of
the questionnaire and will post them on the USMARC list before the
current proposal is discussed at the February meetings of the
USMARC Advisory Group.  The questionnaire addressed the following
issues:
         Amount of time needed to validate new fields/subfields
         Types of changes needed to system for new field/subfield
         Need for and timing of retrospective conversion
         A possible algorithm to be used by systems for conversion
         Possible improvements to system if subfield $v were available

In an earlier discussion of this issue (Discussion Paper No. 74:
Defining a New Subfield Code for Form Subdivisions in the USMARC
Bibliographic/Authority/Classification/Community Information
Formats) there was no consensus as to whether or not a
retrospective conversion of bibliographic and authority records
would be necessary if the new subfield is defined.  It had been
noted that, if a thesaurus has clear rules as to what is a form
subdivision, such a conversion would be possible to accomplish. 
Conversion of LCSH strings could prove problematic in many cases,
although, generally, form subdivisions appear as the last subfield
in a string.  Thus, programs could be designed to catch most but
not all subdivisions in LCSH strings.  If a conversion is not done,
records will be inconsistent, and display and search results could
be confusing.  The survey does attempt to deal further with this
issue.


2.  DISCUSSION

Form data have been defined by the Subject Analysis Committee as
follows:

         "Form data are those terms and phrases that designate specific
         kinds or genres of materials.  Materials designated with these
         terms or phrases may be determined by an examination of:
                 - their physical character (e.g., videocassettes,
                 photographs, maps, broadsides)
                 - the particular type of data that they contain (e.g.,
                 bibliographies, questionnaires, statistics)
                 - the arrangement of information within them (e.g.,
                 diaries, outlines, indexes)
                 - the style, technique, purpose, or intended audience
                 (e.g., drama, romances, cartoons, commercials, popular
                 works)
                 - or a combination of the above (e.g., scores)
         A single term may be modified by other terms, in which case
         the whole phrase is considered to be form data (e.g., aerial
         photographs, French dictionaries, conversation and phrase
         books, wind ensemble suites, telephone directories, vellum
         bound books, science fiction)."

The following are reasons why it was considered desirable to define
a new subfield code for form subdivisions by SAC and the Subject
Subdivisions Conference.  

         - to facilitate compression of online displays in online
         public access catalogs by allowing for the general
         categorization of subdivisions of the focus term by form as
         well as by geographic, chronological, and general subdivision
         - to make displays in online catalogs more helpful listings of
         headings
         - to allow for greater precision in searching
         - to reduce the number of authority records required so that
         separate records are not required for every topic-form pair
         - to provide more effective machine manipulation for database
         maintenance and validation.  It would allow for machine
         validation systems to ignore form subdivisions
         - information in the new form subfield could easily be moved
         to field 655 (Index Term--Genre/Form) at a later date if
         agencies decide to make more widespread use of that field

Concept-based display.  It has been noted that most catalog users
do not look past the first screen when browsing in specified
subject terms in a library catalog. Currently, one of the many
obstacles in the way of effective subject access in online catalogs
is the excessive length of the index display under a specified
search term.  It has been argued that browsing large subject
indexes could be more effective if subdivisions were grouped
conceptually, rather than alphabetically, to provide further
definition of the original concept.  A compressed, conceptually-
based display would summarize the scope of the library's collection
on a particular topic in a single screen by consolidating
subdivided headings into categories.  
In 600-651 fields, form subdivision information could be
distinguished from general subdivision information by defining a
new subfield $v specifically for form information.  This would
allow for a display with greater flexibility.  A general message
for all records subdivided by a particular subfield code could be
substituted, which would vastly reduce the size of index displays. 
For instance, in the case of the $z subfield code for geographic
subdivision, text in the index display could be a phrase such as
"subdivided by geographical area" (e.g., Islam and politics--
SUBDIVIDED BY GEOGRAPHICAL AREA, E.G. AFGHANISTAN).  The same could
be said for subfield code $y and the new subfield code for form. 
A user could thus use such information to decide to further search
or to not search such information.

         Example of such a display:
         
         English literature -- SUBDIVIDED BY CHRONOLOGICAL PERIOD
         English literature -- SUBDIVIDED BY FORM OR TYPE OF MATERIAL
         English literature -- SUBDIVIDED BY GEOGRAPHIC AREA

It should be noted, however, that with LCSH strings, such an
abbreviated display reflects only the nature of the subdivisions at
the level of the first subdivision.  Selecting and viewing English
literature -- SUBDIVIDED BY FORM OR TYPE OF MATERIAL does not
retrieve all instances of form subdivisions in strings that begin
with English literature.  Strings with English literature
subdivided by geographic or chronological subdivisions may
themselves have additional form subdivisions.  However, whether
display designers and system vendors will make more use of subfield
coding with the addition of a new subfield $v has been questioned. 

Distinguishing dual functioning subdivisions.  How to control dual
functioning subdivisions in authority records also needs to be
considered.  It may be a problem for systems that validate against
an authority file to control the dual functions of these
subdivisions if the subdivision is sometimes coded as $x and other
times as $v.  If authority records are created for subdivisions,
those subdivisions that may function either as a general
subdivision or as a form pose a choice: would the subdivision be
established as a 180 field (Heading--General Subdivision) or a new
field 183 (Heading--Form Subdivision)?  These issues need to be
resolved before any implementation.  Theoretically, most form
subdivisions can also function as topical subdivisions.  For
example the subdivision periodicals usually functions as a form in
a subject heading string, indicating that the work is a periodical
on a particular topic.  For instance "United States -- History --
Periodicals" is used for a periodical about United States history. 
"Periodicals" can also function as a topical subdivision as in
"Chemistry -- Periodicals -- History", for a work about the history
of periodicals in the field of chemistry.  

Another example of a dual functioning subdivision in LCSH is
Folklore.  It is used as a form subdivision to identify folklore
texts, e.g. collections of tales or legends of a group of people. 
It is also used as a general subdivision to identify works that
discuss the folklore of particular topics or groups of people.  For
instance, Indians of North America -- Folklore is used for texts of
their legends or discussions about them.  If the subdivision were
distinguished by subfield coding, the following two examples are
possible:

         650  $aIndians of North America $vFolklore  
         [For collections of folklore of North American Indians]

         650  $aIndians of North America $xFolklore
         [For discussions about the folklore of North American Indians]

In this case, both subdivisions occur at the end of the string.

Conversion of existing records.  If the new subfield is defined and
a retrospective conversion is deemed desirable, existing records
could be converted through a global update using the list of form
subdivisions in the particular thesaurus.   The following explores
a possible algorithm and how it might be applied; it appeared in
the Form subdivision survey, initially distributed in September on
the USMARC list:

         "By retrospective conversion, I am referring to a special
         project to identify form subdivisions in subfield $x of
         subject headings in existing files and then move them to
         subfield $v of the same  subject heading.  Such a conversion
         may need to be performed on all databases.  
   
         To undertake such a conversion, your computer program would
         need several lists, such as:  
         - a list of approved form subdivisions for each subject
         thesaurus.  
         - a list of dual-function subdivisions if applicable for a
         specific thesaurus.  
   
         A computer algorithm summarized as follows might be used:  
         (1)  In 600-651 fields, look for occurrence of terms which
         match those present on the list of approved form subdivisions
         for the specific thesaurus.  If found, continue to next step. 
         
         (2)  Check the term against the list of dual-function form
         subdivisions if available for the specific thesaurus.  If
         there is a match, print out the information for human review
         and editing.  Otherwise, continue to next step.  
         (3)  Check to see if the term is the last subfield in the
         field.  If this is the case, change the subfield delimiter
         from $x to $v.  If this is not the case, print out the
         information."

Training requirements.  Subject thesauri systems will have to
provide documentation as well as revise existing documentation to
guide catalogers in the correct assignment of subfield codes for
form subdivisions.  Training and retraining of catalogers will be
needed.


3.       POSSIBLE LIBRARY OF CONGRESS IMPLEMENTATION

The Library of Congress recognizes the need to distinguish form
data in bibliographic records in order to manipulate it for
display, retrieval, and validation of headings.  However, debate
continues about the best place to record and store form data in
MARC bibliographic records-- whether to retain it in separately
coded subfields of subject heading strings, to remove it to a
separate field, such as the 655, or to employ a combination of
methods.  LC feels that further study needs to be undertaken to
determine the optimum method.  Currently, LC uses the 655 field in
limited situations in its bibliographic records.  LC needs to
develop a comprehensive plan for using the 655 field with LCSH.

Application of a new subfield code to identify form subdivisions in
LCSH depends upon LC's ability to provide a list of form
subdivisions that identifies those that may also function as
topical subdivisions, and to provide clear instructions for coding
them.  The best way to handle authority records for dual
functioning subdivisions in the LC Subject Authority File needs to
be determined before LC can implement a new subfield code.  Should
they be coded in the authority record as $v with an indication that
they can also function as $x, or would two authority records be
needed, one with the subdivision in an $x and one with it in a $v? 
Could systems handle records having identifcal text that is coded
differently?

After these issues are resolved, LC plans to implement a new
subfield code for form subdivisions in current cataloging if this
proposal is approved.  Possible retrospective conversion of LC's
bibliographic database could only be considered within the context
of other pending automation projects and after global update is
implemented.


3.       RELATED ISSUES

The following issues need to be considered as part of this
proposal.  Results of the survey, which will be compiled and
distributed on the USMARC list prior to ALA, may assist in arriving
at decisions.

1.  Retrospective conversion  
         *       Would it be necessary to convert existing records to use
                 the new subfield for form subdivision?  Does it make
                 sense for some systems to convert and others not to?
         *       If there is no retrospective conversion, what would be
                 the implications for searching and display of a file that
                 is mixed, with earlier records using $x for form
                 subdivisions, and later records using $v?  Would it make
                 the displays more confusing if no conversion were done?

2.  Use of subfield $v
         *       Is it a possible solution to only use $v in certain
                 thesauri (e.g., MeSH, AAT)?  Could LCSH be excluded or
                 could it be implemented for LCSH on a limited basis?  How
                 might this type of solution be affected by record
                 exchange?

3.  Authority control
         *       How will LCSH authority records be controlled for dual
                 functioning subdivisions?
         *       Should LC look at finding ways to eliminate some dual
                 functioning subdivisions?
         *       For systems that check against the authority file, how
                 will machine validation work if form subdivisions are
                 coded in the authority file as such (in subfield $v or in
                 field 183), if in the bibliographic record it is
                 functioning (and coded) as a general subdivision?  Should
                 they be always coded in the authority record as $v with
                 an indication that they can also function as $x?  Or
                 would two authority records be needed, one with the
                 subdivision in $x and one with it in $v?  Could a system
                 handle it if the identical text were in two different
                 records coded differently?


5.       PROPOSED CHANGES

         The following is presented for consideration:

         -       Define subfield $v (Form subdivision) in the following
                 field blocks:
                         6XX (Bibliographic)
                         1XX (Authority)
                         4XX (Authority)
                         5XX (Authority)
                         7XX (Classification)
                         6XX (Community Information
                 Subfield $v will be defined as follows:
                 Subfield $v contains a form subdivision that designates
                 a specific kind or genre of material as defined by the
                 thesaurus being used.  Subfield $v is appropriate only
                 when a form subject subdivision is added to a personal
                 name, corporate name, name/title, uniform title,
                 geographic name, topical, or genre heading to form an
                 extended subject heading.  Subfield $v is used for form
                 terms when they function as indicated above; the terms
                 are coded in subfield $x if they function as general
                 subdivisions.  A form subdivision in subfield $v is
                 generally the last subfield in the string.  The subfield
                 may be repeated if more than one form subdivision is
                 used.

         -       Change the definition of subfield $x (General
                 subdivision) in the above fields as follows:
                 Subfield $x contains a subject subdivision that is not
                 more appropriately contained in subfields <$v, (Form
                 subdivision),> $y (Chronological subdivision) or $z
                 (Geographic subdivision).  Subfield $x is appropriate in
                 the X00 fields only when a topical subject subdivision is
                 added to a name or name/title heading to form an extended
                 subject heading.

         -       Define fields 183 (Heading--Form Subdivision), 483 (See
                 From Tracing--Form Subdivision), 583 (See Also From
                 Tracing--Form Subdivision), 783 (Subdivision Linking
                 Entry--Form Subdivision)
         
         See Attachment A for a list of fields requiring the changes if
         the new subfield code for form were approved.
         See Attachment B for a possible description and examples of
         subfields $x and $v.
         See Attachment C for a possible description of field X83.

------------------------------------------------------------------
ATTACHMENT A

         Bibliographic format
         600  Subject Added Entry--Personal Name
         610  Subject Added Entry--Corporate Name
         611  Subject Added Entry--Meeting Name
         630  Subject Added Entry--Uniform Title
         650  Subject Added Entry--Topical Term
         651  Subject Added Entry--Geographic Name
         654  Subject Added Entry--Faceted Topical Terms
         655  Index Term--Genre/Form  (the form in subfield $a is a
         genre or form and it can also be subdivided in a subfield $x
         by a general subdivision)
         656  Index Term--Occupation
         657  Index Term--Function
         755  Added Entry--Physical Characteristics

         Authority format
         100  Heading--Personal Name
         110  Heading--Corporate Name
         111  Heading--Meeting Name
         130  Heading--Uniform Title
         150  Heading--Topical Term
         151  Heading--Geographic Name
         180  Heading--General Subdivision
         181  Heading--Geographic Subdivision
         182  Heading--Chronological Subdivision
         
         400  See From Tracing--Personal Name
         410  See From Tracing--Corporate Name
         411  See From Tracing--Meeting Name
         430  See From Tracing--Uniform Title
         450  See From Tracing--Topical Term
         451  See From Tracing--Geographic Name
         480  See From Tracing--General Subdivision
         481  See From Tracing--Geographic Subdivision
         482  See From Tracing--Chronological Subdivision
         
         500  See Also From Tracing--Personal Name
         510  See Also From Tracing--Corporate Name
         511  See Also From Tracing--Meeting Name
         530  See Also From Tracing--Uniform Title
         550  See Also From Tracing--Topical Term
         551  See Also From Tracing--Geographic Name
         580  See Also From Tracing--General Subdivision
         581  See Also From Tracing--Geographic Subdivision
         582  See Also From Tracing--Chronological Subdivision


         Classification format
         700  Index Term--Personal Name
         710  Index Term--Corporate Name
         711  Index Term--Meeting Name
         730  Index Term--Uniform Title
         750  Index Term--Topical
         751  Index Term--Geographic Name
         754  Index Term--Faceted Topical Terms


         Community information format
         600  Subject Added Entry--Personal Name
         610  Subject Added Entry--Corporate Name
         611  Subject Added Entry--Meeting Name
         630  Subject Added Entry--Uniform Title
         650  Subject Added Entry--Topical Term
         651  Subject Added Entry--Geographic Name
         651  Subject Added Entry--Geographic Name
         654  Subject Added Entry--Faceted Topical Terms
         656  Index Term--Occupation
         657  Index Term--Function
                 
------------------------------------------------------------------
                                                ATTACHMENT B

(From field X00 in USMARC Authority Format)
[ ] indicates deletion; < > indicates addition

<$v - Form subdivision
        Subfield $v contains a form subdivision that designates a
        specific kind or genre of material as defined by the thesaurus
        being used.  Subfield $v is appropriate only when a form
        subject subdivision is added to a personal name, corporate
        name, name/title, uniform title, geographic name, topical, or
        genre heading to form an extended subject heading.  Subfield
        $v is used for form terms when they function as indicated
        above; the terms are coded in subfield $x if they function as
        general subdivisions.  A form subdivision in subfield $v is
        generally the last subfield in the string. The subfield may be
        repeated if more than one form subdivision is used.

          100     0#$aGautama Buddha$vBiography$vEarly works to 1800
          100     3#$aClark family$vFiction >
  
$w - Control subfield  [400/500]
        Subfield $w contains up to four character positions
        (designated as $w/0, $w/1, etc.) that indicate whether special
        instructions apply to the display of the heading and whether
        a tracing is restricted to the reference structure of a
        particular type of authority.  Subfield $w is appropriate only
        in the 400 See From Tracing and 500 See Also From Tracing
        fields.  Guidelines for applying the codes defined for
        subfield $w are provided in the Tracing and Reference
        Fields -- General Information section.

$x - General subdivision
     Subfield $x contains a subject subdivision that is not more
     appropriately contained in subfields <$v, (Form subdivision),>
     $y (Chronological subdivision) or $z (Geographic subdivision). 
     Subfield $x is appropriate in the X00 fields only when a topical
     subject subdivision [or a form subject subdivision] is added to
     a name or name/title heading to form an extended subject
     heading.

        100  1#$aBrunhoff, Jean de,$d1899-1937$xCharacters$xBabar
        [100 0#$aGautama Buddha$xBiography$xEarly works to 1800]
        100  1#$aTatlin, Vladimir Evgrafovich,$d1885-1953.$tMonument
              to the Third International $xCopying
        100  0#$aNapoleon$bI,$cEmperor of the French,$d1769-1821
              $xAssassination attempt, 1800 (December 24)
        400  1#$aWashington, George,$d1732-1799$xExpedition, 1753-1754

$y - Chronological subdivision
     Subfield $y contains a subject subdivision that represents a
     period of time. Subfield $y is appropriate in the X00 fields
     only when a chronological subject subdivision is added to a name
     or name/title heading to form an extended subject heading.

        100  1$$aShakespeare, William,$d1564-1616$xCriticism and
              interpretation$xHistory$y18th century

------------------------------------------------------------------
                                                ATTACHMENT C
                                           USMARC Authority Format

X83   Form Subdivisions -- General Information

        183     Heading -- Form Subdivision  (NR)
        483     See From Tracing -- Form Subdivision  (R)
        583     See Also From Tracing -- Form Subdivision  (R)


Indicators

  First         Undefined
     #            Undefined

  Second        Undefined
     #            Undefined

Subfield Codes

              Subdivision term portion
     $v     Form subdivision  (R)
     $y     Chronological subdivision  (R)
     $x     General subdivision  (R)
     $z     Geographic subdivision  (R)

              Tracing and linking subfields
     $i     Reference instruction phrase  [483/583]  (NR)
     $w     Control subfield  [483/583]  (NR)
     $5     Institution to which field applies  [483/583]  (NR)
     $6     Linkage  (NR)



GUIDELINES FOR APPLYING CONTENT DESIGNATORS

        The content designators identify the subelements occurring in
form subdivision headings constructed according to generally
accepted thesaurus-building conventions (e.g., "Library of Congress
Subject Headings, Medical Subject Headings").  A form subdivision
is used as a subdivision portion of an extended subject or index
term access field in bibliographic records.  A form term that is
used as the lead element of an established heading record is
contained in a 150 (Heading -- Topical Term) field.

        The content designators defined for field 783 (Subdivision
Heading Linking Entry -- Form Subdivision) in the first indicator
position and the subdivision term portion and control subfield $6
are described in this section and are not repeated in the field 783
description.  The content designators unique to the heading linking
entry fields are described in the 7XX Heading Linking
Entries -- General Information section.


 INDICATORS

        Both indicator positions are undefined; each contains a blank
(#).


 SUBFIELD CODES

$i - Reference instruction phrase  [483/583]
     Subfield $i contains a reference instruction phrase other than
     those that may be system generated from the field tag or from
     the codes defined for subfield $w (Control subfield).  Subfield
     $i is appropriate only in the 483 See From Tracing and 583 See
     Also From Tracing fields.  Guidelines for applying subfield $i
     are provided in the Tracing and Reference Fields -- General
     Information section.


$w - Control subfield  [483/583]
     Subfield $w contains up to four character positions (designated
     as $w/0, $w/1, etc.) that indicate whether special instructions
     apply to the display of the heading and whether a tracing is
     restricted to the reference structure of a particular type of
     authority.  Subfield $w is appropriate only in the 483 See From
     Tracing and 583 See Also From Tracing fields.  Guidelines for
     applying the codes defined for subfield $w are provided in the
     Tracing and Reference Fields -- General Information section.


$v - Form subdivision
     Subfield $v contains a form subdivision that designates a
     specific kind or genre of material as defined by the thesaurus
     being used.  

        183  ##$vFiction

        040  ##$aDNLM#cDNLM
        183  ##$vcase studies$vsoftware

$x - General subdivision
     Subfield $x contains a subject subdivision that is not more
     appropriately contained in subfields $v, (Form subdivision), $y
     (Chronological subdivision) or $z (Geographic subdivision). 
     Subfield $x is appropriate in the X00 fields only when a topical
     subject subdivision is added to a name or name/title heading to
     form an extended subject heading.
     Subfield $x contains a topical or language subdivision term. 
     Subfield $x is appropriate in an X83 field only when a general
     subdivision is added to a form subdivision to form an extended
     subdivision heading.


$y - Chronological subdivision
     Subfield $y contains a subdivision term that represents a period
     of time.  Subfield $y is appropriate in an X83 field only when
     a chronological subdivision is added to a form subdivision to
     form an extended subdivision heading.


$z - Geographic subdivision
     Subfield $z contains a geographic name subject subdivision. 
     Subfield $z is appropriate in an X83 field only when a
     geographic subdivision is added to a form subdivision to form an
     extended subdivision heading.


$5 - Institution to which field applies  [483/583]
     Subfield $5 contains the USMARC code for the organization that
     has added a tracing field to a national authority file record. 
     Subfield $5 is appropriate only in the 483 See From Tracing and
     583 See Also From Tracing fields.  Guidelines for applying
     subfield $5 are provided in the Tracings and Reference
     Fields -- General Information section.


$6 - Linkage
     Subfield $6 contains data that link pairs of fields that are
     alternate graphic representations of each other.  It contains
     the tag number of an associated field and an occurrence number. 
     A complete description of subfield $6 and guidelines for
     applying it are provided in the 882 Alternate Graphic
     Representation section.


INPUT CONVENTIONS

Punctuation

The punctuation of the subelements of a heading is generally
dictated by subject heading system/thesaurus rules.  These input
conventions clarify USMARC punctuation practices.

An X83 field does not end with a mark of punctuation unless the
field ends with an abbreviation, an initialism, or data that ends
with a mark of punctuation.


Spacing

No spaces are used in initialisms.


One space is used after an open-ended date when it is followed by
another subfield.

One space is used between the final period of an abbreviated term
and a word that follows.


Display Constant

   --      [dash associated with the content of subfield $v, $x, $y, or
$z]

The dash ( -- ) that precedes a subject subdivision heading is not
carried in the USMARC record.  It may be system generated as a
display constant associated with the content of subfield $v, $x,
$y, or $z.


Use of subfields $x, $y, and $z

For LCSH, subfields $x (General subdivision), $y (Chronological
subdivision), and $z (Geographic subdivision) are unlikely to be
used in conjunction with field X83, since the form subdivision
would generally not be followed by another subdivision when it is
functioning as a form.


RELATED USMARC FIELD OR DOCUMENT

        7XX     Heading Linking Entries -- General Information
        783     Subdivision Heading Linking Entry -- Chronological
                  Subdivision
        880     Alternate Graphic Representation
        Tracing and Reference Fields -- General Information


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Library of Congress Help Desk (09/03/98)