020 Subfield $a - International Standard Book Number:

Subfield $a contains a valid ISBN for the item. Parenthetical qualifying information, such as the publisher/distributor, binding/format, and volume numbers, is not separately subfield coded. ISBN and the embedded hyphens may be generated.

Examples:

020 ##$a0491001304

020 ##$a0717941728 (folded) :$c$0.45

020 ##$a0914378260 (pbk. : v. 1)$c$5.00

020 ##$a0394502884 (Random House) :$c$12.50

020 ##$a0394170660 (Random House : pbk.) :$c$4.95

[Two ISBNs associated with one catalog record.]

020 ##$a0877790086 :$c$10.00

020 ##$z0877790105 (Fabrikoid) :$c$12.00

020 ##$a0877790019 (black leather)$z0877780116 :$c$14.00

020 ##$a0877790124 (blue pigskin) :$c$15.00

020 ##$z0877790159 (easel binding) :$c$16.00

[Five numbers associated with one catalog record. Two are valid; one has both a valid and invalid form; two are invalid.]

020 ##$a0456789012 (reel l)

020 ##$z0567890123 (reel 2)

[Two numbers associated with one catalog record.]

To return, select:

020 International Standard Book Number