The identification number assigned to each discrete Resource within a Repository.
Use collection number as the unique identifier. Collection number consists of either AC (MIT records) or MC (manuscript collections) and a four digit number.
Component Unique Identifier
At collection level use for series level description:
Use Arabic numerals for series numbers; express in digits.
When using on a file or item level:
Generally used for a barcode when a folder or item is being digitized.