MARC bibliographic records may contain classification numbers in fields 050-09X.  MARC authority records may contain classification numbers in fields 053 (LC Classification Number) and 083 (Dewey Decimal Classification Number).  Classification numbers may be valid, invalid or, in the case of a span, partially valid.

   A valid classification number may be used in a bibliographic or authority record by itself or with additional letters or numbers.  In the case of a span, a portion of it may be used in a bibliographic record.  In addition, a number that has been synthesized by correctly applying a table, internal subarrangement or add instructions to a classification number or span is considered valid for use in a bibliographic or authority record; a classification record may or may not be created for synthesized numbers or numbers within spans.

   A partially valid classification number span is one in which only the beginning or ending number of a span is valid.  Only the valid portion may be used in bibliographic or authority records.

   An invalid number may not be used in a bibliographic or authority record.  However, a classification record may be created for an invalid number in cases where the reference information cannot be communicated by a simple 453 tracing because a more detailed reference note is required.  Invalid numbers in a 153 field of an invalid record or in a 453 (Invalid Number Tracing) field may not be used in bibliographic or authority records.

See also:

Classification Data Format:  Introduction