"1999-07-02"^^ . . "Recommended best practice is to identify the resource by means of a string conforming to a formal identification system. "@en . "2008-01-14"^^ . "A second property with the same name as this property has been declared in the dcterms: namespace (http://purl.org/dc/terms/). See the Introduction to the document \"DCMI Metadata Terms\" (http://dublincore.org/documents/dcmi-terms/) for an explanation."@en . . "An unambiguous reference to the resource within a given context."@en . "Identifier"@en . .