<?xml version=“1.0” encoding=“UTF-8”?> <SearchParameter xmlns=“hl7.org/fhir”>

<id value="example-extension"/>
<meta>
  <security>
    <system value="http://terminology.hl7.org/CodeSystem/v3-ActReason"/>
    <code value="HTEST"/>
    <display value="test health data"/>
  </security>
</meta>
<url value="http://hl7.org/fhir/SearchParameter/example-extension"/>
<name value="Example Search Parameter on an extension"/>
<status value="draft"/>
<experimental value="true"/>
<publisher value="Health Level Seven International (FHIR Infrastructure)"/>
<contact>
  <telecom>
    <system value="url"/>
    <value value="http://hl7.org/fhir"/>
  </telecom>
</contact>
<description value="Search by url for a participation agreement, which is stored in a DocumentReference"/>
<code value="part-agree"/>
<base value="Patient"/>
<type value="reference"/>
<expression value="DocumentReference.extension('http://example.org/fhir/StructureDefinition/participation-agreement')"/>
<xpath value="f:DocumentReference/f:extension[@url='http://example.org/fhir/StructureDefinition/participation-agreement']"/>
<xpathUsage value="normal"/>
<target value="DocumentReference"/>

</SearchParameter>