"The RelatedArtifact structure defines resources related to a module such as previous and next versions of documents, documentation, citations, etc. Note that the name resource here is being used in a more general sense than the FHIR-specific Resource. The related resource may be a FHIR resource, or it may be another type of resource, represented using the Attachment data type." - HL7 FHIR, RelatedArtifact