"Occurrence ID" . "2009-04-24" . . "2008-11-19" . "recommended" . . "An identifier for the Occurrence (as opposed to a particular digital record of the occurrence). In the absence of a persistent global unique identifier, construct one from a combination of identifiers in the record that will most closely make the occurrenceID globally unique." . . . . "DataSets/DataSet/Units/Unit/UnitGUID" . . "For a specimen in the absence of a bona fide global unique identifier, for example, use the form: \"urn:catalog:[institutionCode]:[collectionCode]:[catalogNumber]. Examples: \"urn:lsid:nhm.ku.edu:Herps:32\", \"urn:catalog:FMNH:Mammal:145732\"" .