Specifies the conformance requirements for HL7 FHIR DocumentReference resources used to register and retrieve clinical documents in the myHealth ecosystem. A DocumentReference acts as a pointer to a clinical document (e.g. PDF, CDA, or FHIR Composition), capturing its metadata (type, status, author, custodian, content URL) without necessarily including the document content itself. It is the primary mechanism for document-based exchange in the myHealth cross-border scenario.