==0 – Блок ідентифікації== This block contains those numbers that identify the item or the copy recorded in it. *[[hold/001|001 Holdings Record Identifier]]*[[hold/004|004 Related Bibliographic Record Identifier]]*[[hold/005|005 Version Identifier]]*[[hold/035|035 Other Systems Control Number]]*[[hold/070|070 Inventory Number]] ==Occurrence== Fields [[hold/001|001]] and [[hold/004|004]] are mandatory in every record. Other fields are entered when data is available.