<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="questionnaire-referenceFilter" />
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-wg">
    <valueCode value="fhir" />
  </extension>
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm">
    <valueInteger value="1" />
  </extension>
  <url value="http://hl7.org/fhir/StructureDefinition/questionnaire-referenceFilter" />
  <name value="referenceFilter" />
  <status value="draft" />
  <date value="2013-07-04" />
  <publisher value="HL7" />
  <contact>
    <telecom>
      <system value="url" />
      <value value="http://www.hl7.org" />
    </telecom>
  </contact>
  <description value="Identifies a filter to apply when looking up candidate answers for the question." />
  <fhirVersion value="3.0.1" />
  <mapping>
    <identity value="rim" />
    <uri value="http://hl7.org/v3" />
    <name value="RIM Mapping" />
  </mapping>
  <kind value="complex-type" />
  <abstract value="false" />
  <contextType value="resource" />
  <context value="Questionnaire.item" />
  <context value="Questionnaire.item.item" />
  <contextInvariant value="type='reference'" />
  <type value="Extension" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Extension" />
  <derivation value="constraint" />
  <differential>
    <element id="Extension">
      <path value="Extension" />
      <short value="Filter to apply when looking up references" />
      <definition value="Identifies a filter to apply when looking up candidate answers for the question." />
      <comment value="The filter may include $subj and/or $encounter which should be substituted by the implementer with the subject and/or encounter id relevant in the context in which the questionnaire is being populated." />
      <min value="0" />
      <max value="1" />
      <mapping>
        <identity value="rim" />
        <map value="N/A - MIF rather than RIM level" />
      </mapping>
    </element>
    <element id="Extension.extension">
      <path value="Extension.extension" />
      <max value="0" />
    </element>
    <element id="Extension.url">
      <path value="Extension.url" />
      <type>
        <code value="uri" />
      </type>
      <fixedUri value="http://hl7.org/fhir/StructureDefinition/questionnaire-referenceFilter" />
    </element>
    <element id="Extension.valueString">
      <path value="Extension.valueString" />
      <type>
        <code value="string" />
      </type>
    </element>
  </differential>
</StructureDefinition>