Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Visual and Verbal Communication (hierarchy name)
4. Information Forms (hierarchy name)
5. information forms (objects)
6. information artifacts
7. [information artifacts by function]
8. identifying artifacts
9. identification numbers and codes

Anotations

Scope note:

Unique numeric, alphabetic, alphanumeric, or other codes that identify or reference a thing, concept, or record, and that are reliable and longlasting. An example of a persistent identifier is as used for digital objects. Persistent identifier systems include "persistent object identifiers" (POIDs) and "digital object Identifiers" (DOIs).