doi in External_​Reference

Name: doiVersion Id:
Description: The doi attribute provides the Digital Object Identifier for an object, assigned by the appropriate DOI System Registration Agency.
Namespace Id: pdsSteward: pdsClass Name: External_​ReferenceType: ASCII_​DOI
Minimum Value: NoneMaximum Value: NoneMinimum Characters: NoneMaximum Characters: None
Unit of Measure Type: NoneDefault Unit Id: NoneAttribute Concept: DOIConceptual Domain: Short_String
Status: ActiveNillable: falsePattern: 10\.\S+/\S+
Permissible Value(s)No Values