represents a resource identified by id in the external identifier system "type".


includes the metadata given by the association meta to this instance of the external identifier object.


  • id is usually a string. Other expressions like integers are supported for certain external identifier types.
  • If meta contains a key "Label", then the corresponding value is used for display.
  • ExternalIdentifier[...]["prop"] can be used to access data about identifiers. Properties include:
  • "Type"the external identifier type
    "ExternalID"the raw identifier
    "Label"the label of the resource stored in meta
    "Description"the description of the resource stored in meta
    "URL"a URL to a description of the resource
    "Hyperlink"a Hyperlink to a description of the resource
    "ConceptURI"a URL identifying the resource
  • The value of the "ConceptURI" identifies a resource in the semantic web. When dereferenced, it usually redirects to a machine- or human-readable description of the resource.
  • The value of "URL" typically defaults to the value of "ConceptURI".
  • Values of "Hyperlink" are obtained by applying Hyperlink to non-missing values of "URL".


Basic Examples  (2)

Enter a DOI representing a scientific article:

Specify a "Label":

Extract a raw identifier:

Get a hyperlink:

Introduced in 2020