A date associated with an event in the life cycle of the
resource.
http://www.w3.org/2000/01/rdf-schema#isDefinedBy
http://purl.org/dc/elements/1.1/
http://purl.org/dc/elements/1.1/description
Typically, Date will be associated with the creation or
availability of the resource. Recommended best practice
for encoding the date value is defined in a profile of
ISO 8601 [W3CDTF] and follows the YYYY-MM-DD format.