Definition and scope:

A cross reference is used to refer between classification numbers that are constructed according to the classification scheme that is identified in field 084 (Classification Scheme and Edition).  It leads from an invalid classification number to a valid classification number or from one valid classification number to another valid classification number.  Tracings or reference note fields are used to direct the user to another classification number, often for specific aspects of a topic.  Cross reference displays may be generated by combining the contents of a tracing or a reference note field and field 153 (Classification Number) of a record.  In some cases, the inputting library may provide both a tracing and a reference note field and choose to suppress the tracing for display purposes.

The Tracings and References - General Information section describes the use of the various reference note fields and tracings fields in constructing displays of cross references from these fields.  It also provides instructions for applying subfields $i (Reference instruction phrase), $t (Topic), and $w (Control subfield) in the 453 and 553 tracing fields.  The individual field description for each of the reference note fields (253 and 353) contains the detailed instructions for the content designators for that field.  Refer to the Tracings and References - General Information section only for cross reference display descriptions.  The 453 and 553 descriptions refer to both the X53 and the Tracings and References - General Information sections for content designator instructions.

For additional information on the Tracing and Reference fields, select:

Tracing fields and Simple cross references


084  0#  $alcc  [Library of Congress Classification]

153  ##  $aHD1330$cHD1331$hIndustries. Land use. Labor$hLand use$hLand tenure$jLandlord and peasant

453  00  $wj$aHD1501.2$hIndustries. Land use. Labor$hAgricultural economics$jLandlord

[An invalid classification number in field 453 leads the user to the valid classification number span in field 153.]

Cross reference display example:

Industries. Land use. Labor

Agricultural economics

Landlord see HD1330-HD1331

[Note:  The invalid number in 453$a may be suppressed for display.]

453 / 553 Subfield Codes for Tracing Fields:  (Guidelines for applying content designators)




Subfield code:




Reference instruction phrase






Control subfield



/0   Special relationship



a  Previous classification number



b  New classification number



i   Reference instruction phrase in subfield $i



j   See reference



k  Class elsewhere reference  [553 only]



l   See also reference  [553 only]



m Standard subdivisions do-not-use reference



n  Not applicable



/1   Hierarchical relationship



g  Number representing broader topic



h  Number representing narrower topic



n  Not applicable



/2   Reference display



a  Reference not displayed



n  Not applicable



/3   History reference



a  History reference, field 685 used



n  Not applicable


Reference note fields and Complex cross references


008/06  b  [table record]

084  0#  $addc$c22  [Dewey Decimal Classification]

153  ##  $a621.47$hTechnology (Applied sciences)$hEngineering and applied operations$hApplied physics$hHeat engineering and prime movers$jSolar-energy engineering

253  2#  $iClass engineering of secondary sources of solar energy with the secondary source, e.g., generation of electricity from solar radiation$a621.31244,$iwind energy$a621.45

[Reference instruction phrase is explicit in 253 subfield $i.]

Cross reference display example at 621.47:

621.47  Solar-energy engineering

Class engineering of secondary sources of solar energy with the secondary source, e.g., generation of electricity from solar radiation 621.31244, wind energy 621.45

Input conventions:  Display constants for cross references

Scheme-specific conventions:  Display constants for cross references

Reference fields:

253  Complex See Reference  (R)

353  Complex See Also Reference  (R)

Tracing fields:

453  Invalid Number Tracing  (R)

553  Valid Number Tracing  (R)

Related MARC fields or documents:

084  Classification Scheme and Edition

X53  Classification Numbers - General Information

685  History Note

See also:

2XX-5XX  Tracings and References

Variable Data Fields