015 - National Bibliography Number (R)

Indicators 1st -  Undefined
  2nd -  Undefined
Subfields _a  Audience term (R)
  _q Qualifying information (R)
  _z Audience code (R)
  _2 Demographic group term (NR)
  _6 Demographic group code (NR)
  _8 Authority record control number or standard number (R)
Examples
015 ## _aGFR67-A14-54
015 ## _aAu67-6
015 ## _aF67-835(v.1)
015 ## _a84-3117
015 ## _2bnf
015 ## _aF67-9455
  _qv.2