Dedupe 4.9
Dedupe 4.9: Optional Group - 020 $a - ISBN(Verify)
International Standard Book Number (ISBN/020)
This field records the International Standard Book Number(s) assigned to a catalogued item. Each valid ISBN is entered in a separate 020 tag; two or more invalid or cancelled ISBNs may be recorded in a single 020 tag.
The following subfields are valid in the 020 tag:
- a - International Standard Book Number
- c - Terms of availability
- z - Cancelled/invalid ISBN
Valid ISBNs are always ten or thirteen digits long; all ISBNs are assumed valid unless they have too many or too few digits, or unless a shelflist card specifically identifies an ISBN as cancelled or invalid:
020 $a 0049812187 020 $a 9780049853217
The only letter that is ever part of an ISBN is X (roman numeral 10); it must always be capitalized:
020 $a 012817409X
Subfield a may contain qualifying information (publisher, binding, format, volume numbers). This information is usually entered within parentheses; separate pieces of information with space-colon-space:
020 $a 001281947X (pbk.) 020 $a 0018942113 (Bally Bros. : pbk.) 020 $a 0137183911 (large print)
Prices appearing after ISBNs are catalogued in subfield c:
020 $a 0174620684 :$c $21.95 020 $a 0049812187 (pbk.) :$c $17.40
For comparing the ISBN, the normalization will remove all spaces and punctuation and will do a special normalization for the ISBN to standardize it. This normalization only happens in the compare of the records within the program, not in the output.
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