Indicates the agency which created the authority record.
$a contains the LC
code for the cataloguing agency: NNUN is the code for the Dag
$b contains the 3-letter code for
the language of the cataloguing agency: eng (English).
$f contains the six-letter code for
the authority heading conventions used: unbist (UNBIS Thesaurus).
040 $a NNUN $b eng f$