doi:IsDerivedFrom
doi:IsManifestationOf
doi:HasSubject
doi:IsReplacementFor
doi:IsPartOf
doi:HasContributor
and this list is just the recommended minimum as explained in the rest of the paragraph.
XML is mandated for the DOI Kernel metadata, i.e. the small set of fields that need to be registered in the DOI central registry to allow identification a some basic interoperability. Essentially, it just lets users understand what kind of entity the DOI refers to. The metadata description available in the system to which the DOI “belongs” is completely up to the system. You do not need to be a Registration Agency to use your own metadata description, the only requirement is being able to extract a DOI Kernel metadata record.
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