| Semantic unit | 1.1.1 objectIdentifierType |
|---|
| Definition | A designation of the domain within which the object identifier is unique. |
| Obligation | Mandatory |
| Repeatability | Not repeatable |
| Rationale | Identifier values cannot be assumed to be unique across domains; the combination of objectIdentifierType and objectIdentifierValue should ensure uniqueness. |
| Data constraint | Value should be taken from a controlled vocabulary. A controlled vocabulary is available at: |
| Controlled vocabulary | http://id.loc.gov/vocabulary/identifiers.html  |
| Usage notes | The type of the identifier may be implicit within the repository as long it is can be explicitly communicated when the digital object is disseminated outside of it. |
| Examples | ISBN (Intellectual Entity) DOI (Intellectual Entity) DLC DRS hdl:4263537 DLC DRS hdl:4263537 DLC DRS hdl:4263537 |
