<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">persistent identifiers</topic></authority><related type="broader"><topic>identification numbers and codes</topic></related><variant type="other"><topic>PI</topic></variant><variant type="other"><topic>identifier, persistent</topic></variant><variant type="other"><topic>persistent identifier</topic></variant> <note xml:lang="en"><![CDATA[ Unique numeric, alphabetic, alphanumeric, or other codes that identify or reference a thing, concept, or record, and that are reliable and longlasting. An example of a persistent identifier is as used for digital objects. Persistent identifier systems include "persistent object identifiers" (POIDs) and "digital object Identifiers" (DOIs). ]]></note></mads>