International Standard Book Number (ISBN) assigned to a monographic publication by designated agencies in each country participating in the program. The field may include terms of availability and canceled or invalid ISBNs, such as ISBNs with invalid check digits or that are not applicable to the item being cataloged. It may be repeated for multiple numbers associated with the item (e.g., ISBNs for the hard bound and paperback manifestations; ISBNs for a set as a whole and for the individual parts in the set).
| 020 | ##$a0491001304 | ||||||||
| 020 | ##$a0914378260$qpbk.$qv. 1$c$5.00 | ||||||||
| 020 | ##$a0394502884$qRandom House$c$12.50 | ||||||||
| 020 | ##$a0877790019$qblack leather$z0877780116 :$c$14.00 | ||||||||
| 020 | ##$c$8.95 | ||||||||
| 020 | ##$cRs15.76 ($5.60 U.S.) | ||||||||
| 020 | ##$a0460044524$cRental material | ||||||||
| 020 | ##$cFor sale ($200.00 for 3/4 in.; $150.00 for 1/2 in.) | ||||||||
| 020 | ##$a0394170660$qRandom House$qpaperback$c$4.95 | ||||||||
| 020 | ##$a0456789012$qreel 1 | ||||||||
| 020 | ##$z0567890123$qreel 2 | ||||||||
| 020 | ##$a9780060723804$qacid-free paper | ||||||||
| 020 | ##$a9780060799748$qtrade | ||||||||
| 020 | ##$a0717941728$qfolded$c$0.45 | ||||||||