<StructureDefinition xmlns="http://hl7.org/fhir">
  <url value="http://example.org/fhir/StructureDefinition/SDCDocumentReference" />
  <name value="SDCDocumentReference" />
  <status value="draft" />
  <fhirVersion value="4.0.0" />
  <kind value="resource" />
  <abstract value="false" />
  <type value="DocumentReference" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/DocumentReference" />
  <derivation value="constraint" />
  <differential>
    <element id="DocumentReference.masterIdentifier">
      <path value="DocumentReference.masterIdentifier" />
      <comment value="The masterIdentifier should be derived from the SDC formID and formInstanceVersionURI in the format of formID.formInstanceVersionURI" />
      <requirements value="The structure and format of this Id shall be consistent with the specification corresponding to the InstanceVersionURI specified in the SDC Technical Reference Guide" />
    </element>
    <element id="DocumentReference.identifier">
      <path value="DocumentReference.identifier" />
      <comment value="Other identifiers associated with the document, including version independent identifiers. Map other SDC Identifiers here including: Lineage, FormID, Version, BaseURI, InstanceURI, FullURI" />
    </element>
    <element id="DocumentReference.relatesTo">
      <path value="DocumentReference.relatesTo" />
      <comment value="Relationships that this document has with other DocumentReferences and Observations. Needs to map to DocumentReference masterIdentifier, and must map to any Observations Identifiers that are derived from this DocumentReference" />
    </element>
    <element id="DocumentReference.content">
      <path value="DocumentReference.content" />
      <comment value="Should provide access to the form as either data or url. " />
    </element>
    <element id="DocumentReference.context">
      <path value="DocumentReference.context" />
      <comment value="Should reference created observations from this form. " />
    </element>
  </differential>
</StructureDefinition>