453 Invalid Number Tracing

Field definition and scope:

Field 453 contains a tracing for a cross reference from an invalid classification number. It is used for a valid or partially valid classification number (008/08 Classification validity, code a, b or c) record to trace a reference from an invalid to a valid number. When a 453 number tracing field cannot adequately convey necessary information about an invalid classification number, a separate record may be created for the invalid number (008/08 Classification validity, code d) containing field 253 (Complex See Reference). In such instances, a 453 number tracing field may also be included in the valid or partially valid classification number record in the record for the valid number if desired. A tracing for a valid classification number that is invalid only for a particular topic is contained in field 553 (Valid Number Tracing).

The content designators used in the classification number and caption portions of field 453 are the same as those defined for fields 153 (Classification Number) and 553 (Valid Number Tracing).

Field 453 is repeatable.

Guidelines for applying content designators:

Guidelines for applying these content designators, including indicators, scheme-specific conventions and input conventions, also are given in the X53 Classification Numbers - General Information section.

Guidelines for applying tracing subfield codes, including scheme-specific conventions and input conventions, also are given in the Tracings and References - General Information section.

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

Position	Description	Repeatability
Field 453	Invalid Number Tracing	R
Indicator:
First	Source of classification number
0	Schedule
1	Table

Second	Undefined; contains a blank

Subfield code:
$a	Classification number element - single number or beginning number of span	R
$c	Classification number element - ending number of span	R
$h	Caption hierarchy	R
$i	Reference instruction phrase	NR
$j	Caption	NR
$k	Summary number span caption hierarchy	R
$t	Topic	NR
$w	Control subfield	NR
	/0 - Special relationship
	a Previous classification number
	b New classification number
	i Reference instruction phrase in subfield $i
	j See reference
	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
$y	Table sequence number for internal subarrangement or add table	R
$z	Table identification	R
$6	Linkage	NR
$8	Field link and sequence number	R

See: Examples for this field.

Input conventions:

Order of subfields

Invalid classification numbers

Number spans

Display of classification numbers and captions

Display constants for cross references

Scheme-specific conventions:

Library of Congress Classification

Note: The Library of Congress Classification scheme does not use subfield $t in field 453.

Dewey Decimal Classification

Display constants for cross references

Content designator history:

Subfield $y - Table sequence number for internal subarrangement or add table [new, 2008]

Subfield $z - Table identification [redefined, 2008]: Subfield $z was redefined as repeatable.