Documentation

h1. Instance

An instance is one specific materialization or version of the result. For example, you can have one result with three instances as result of deduplication:

• one is the pre-print
• one is the post-print
• one is the published version

Each instance is characterized by the properties described in the following table.

|. field name |. cardinality |. type |. description |
| accessright | ONE | AccessRight | Maps "dc:rights":https://www.dublincore.org/specifications/dublin-core/dcmi-terms/elements11/rights/, describes the access rights of the web resources relative to this instance. |
| alternateIdentifier | MANY | AlternateIdentifier | All the identifiers associated to the result other than the authoritative ones |
| articleprocessingcharge | ONE | APC | The money spent to make this book or article available in Open Access. Source for this information is the OpenAPC initiative. |
| license | ONE | string | License URL |
| pid | MANY | ResultPid | The set of persistent identifiers associated to this instance that have been collected from an authority for the pid type (i.e. Crossref/Datacite for doi). See OpenAIRE_entity_identifier_and_PID_mapping_policy for more information. |
| publicationdate | ONE | string | Date of the research product |
| refereed | ONE | string | describes if this instance has been peer-reviewed or not. Allowed values are peerReviewed, nonPeerReviewed, UNKNOWN (as defined in https://api.openaire.eu/vocabularies/dnet:review_levels) |
| type | ONE | string | The specific sub-type of this instance (see https://api.openaire.eu/vocabularies/dnet:result_typologies following the links) |
| url | MANY | string | URLs to the instance. They may link to the actual full-text or to the landing page at the hosting source. |