A persistent identifier is a long-lasting reference to a resource. The data(set) you deposit in a data repository should be assigned a globally unique, persistent and resolvable identifier (PID) so that both humans and machines can find it. Persistent identifiers are maintained and governed so that they remain stable and direct the users to the same relevant object consistently over time. Examples of PIDs include Digital Object Identifier (DOI), Handle, and Archival Resource Key (ARK).