OAI/PMH: Deleted record support
See https://www.openarchives.org/OAI/openarchivesprotocol.html#DeletedRecords
The deleted field must move from the Record to the Document model, maybe.
See https://www.openarchives.org/OAI/openarchivesprotocol.html#DeletedRecords
The deleted field must move from the Record to the Document model, maybe.