Reference and subdivision:

Code g (008/09) indicates that the 15X field contains an unestablished untraced reference heading that is also authorized for use as a subdivision in a subject access point in a bibliographic record. One authority record is used to describe this dual function. The record may also contain a reference note field that explains the dual function.

When separate authority records are created, code b is used for the untraced reference record and code d is used for the subdivision record. An 18X heading field is used in the subdivision record.

Example:

008/09 g

150 ##$aDictionaries

260 ##$isubdivision$aDictionaries$iunder specific subject terms