| COMARC/B | September | 2003 |
This field contains the number allocated to the record of a bibliographic item by the national bibliographic agency, and an indication of the country of the agency.
A number erroneously assigned to a bibliographic record in the bibliography (see example 2).
The preferred form of the national bibliography number entered in subfield b is the form in which it is assigned by the agency including spaces, hyphens and other punctuation. The country code of the country of the national bibliography is entered in subfield a according to ISO 3166.
An erroneous number may be entered in subfield z. When only an erroneous number is known, only subfields a and z are entered.
Within the COBISS.SI system this field is entered only by the National and University Library, Ljubljana. The code "SI" – Slovenia is used in subfield a, and in subfield b the codes are entered from the National and University Library local code list.
020 ⊔⊔ aAU b67-6 (An Australian National Bibliography Number.) 020 ⊔⊔ aCA bCM73-6722XF 020 ⊔⊔ aCA zCM78-6722XF (A correct and an erroneous Canadian number.) 020 ⊔⊔ aDD b83,A16,0553 020 ⊔⊔ aDD b82,N46,0092 (The record for an item in the "Deutsche Bibliographie" contains a repeated field 020 since the item has appeared twice in the "Deutsche Bibliographie"; the earlier version of the record was a CIP record. Though the record containing the repeated fields is simply an upgrade of the CIP record, it includes the earlier number since this is the practise of the agency preparing the record.) 020 ⊔⊔ aGB b82,N46,0092 (A number from the "British National Bibliography".) *
020 ⊔⊔ aSI bM1998K1 (A number from the Slovenian Bibliography of Books.)