The context term relationship requires additional terms before it can be used to full
potential. The DataCite schema http://schema.datacite.org/meta/kernel-3/doc/DataCite-MetadataKernel_v3.1.pdf has a similiar concept that is represented with three properties:

• relatedIdentifier
• relatedIdentifierType
• relationType

for example:

<relatedIdentifier relatedIdentifierType="ISBN"
relationType="IsPartOf">0‐486‐27557‐4
</relatedIdentifier>

I propose that we add the terms relatedIdentifier and relationType using the DataCite controlled list for relationType when verifying instance documents. So for example, an instance doc might have:

   "relationship":{
       "relationshipType":"isPartOf",
       "relatedIdentifier":"urn:uuid:F1A0A7AF-ECF3-4C7D-B675-7C6949963995"
   }

The DataCite list of relation types:

• IsCitedBy
• Cites
• IsSupplementTo
• IsSupplementedBy
• IsContinuedBy
• Continues
• HasMetadata
• IsMetadataFor
• IsNewVersionOf
• IsPreviousVersionOf
• IsPartOf
• HasPart
• IsReferencedBy
• References
• IsDocumentedBy
• Documents
• IsCompiledBy
• Compiles
• IsVariantFormOf
• IsOriginalFormOf
• IsIdenticalTo
• IsReviewedBy
• Reviews
• IsDerivedFrom
• IsSourceOf