453 Invalid Number Tracing (VDF)

453 Invalid Number Tracing (R) (Variable Data Field)

Field definition and scope: This field 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) . Guidelines for applying these content designators, including indicators, scheme-specific conventions and input conventions, are given in the X53 Classification Numbers - General Information section.

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

Field 453 is repeatable .

Guidelines for applying Content Designators:

Indicators

First Source of classification number

0 Schedule

1 Table

Second Undefined; contains a blank (#)

Subfield Codes

$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)