Search parameter for a reference example

{
  "resourceType": "SearchParameter",
  "id": "example-reference",
  "text": {
    "status": "generated",
    "div": "<div xmlns=\"http://www.w3.org/1999/xhtml\"><p><b>Generated Narrative with Details</b></p><p><b>id</b>: example-reference</p><p><b>url</b>: <b>http://hl7.org/fhir/SearchParameter/example-reference</b></p><p><b>name</b>: Example Search Parameter</p><p><b>status</b>: draft</p><p><b>experimental</b>: true</p><p><b>date</b>: 23/10/2013</p><p><b>publisher</b>: Health Level Seven International (FHIR Infrastructure)</p><p><b>contact</b>: </p><p><b>description</b>: Search by condition subject</p><p><b>purpose</b>: Need to search Condition by subject</p><p><b>code</b>: subject</p><p><b>base</b>: Condition</p><p><b>type</b>: reference</p><p><b>expression</b>: Condition.subject</p><p><b>xpathUsage</b>: normal</p><p><b>target</b>: Organization</p><p><b>modifier</b>: missing</p><p><b>chain</b>: name, identifier</p></div>"
  },
  "url": "http://hl7.org/fhir/SearchParameter/example-reference",
  "name": "Example Search Parameter",
  "status": "draft",
  "experimental": true,
  "date": "2013-10-23",
  "publisher": "Health Level Seven International (FHIR Infrastructure)",
  "contact": [
    {
      "name": "[string]",
      "telecom": [
        {
          "system": "url",
          "value": "http://hl7.org/fhir"
        }
      ]
    }
  ],
  "description": "Search by condition subject",
  "purpose": "Need to search Condition by subject",
  "code": "subject",
  "base": [
    "Condition"
  ],
  "type": "reference",
  "expression": "Condition.subject",
  "xpathUsage": "normal",
  "target": [
    "Organization"
  ],
  "modifier": [
    "missing"
  ],
  "chain": [
    "name",
    "identifier"
  ]

  "resourceType" : "SearchParameter",
  "id" : "example-reference",
  "extension" : [{
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
    "valueCode" : "fhir"
  }],
  "url" : "http://hl7.org/fhir/SearchParameter/example-reference",
  "name" : "ExampleSearchParameter",
  "title" : "Example Search Parameter",
  "status" : "draft",
  "experimental" : true,
  "date" : "2013-10-23",
  "publisher" : "HL7 International / FHIR Infrastructure",
  "contact" : [{
    "telecom" : [{
      "system" : "url",
      "value" : "http://www.hl7.org/Special/committees/fiwg"
    }]
  }],
  "description" : "Search by condition subject",
  "purpose" : "Need to search Condition by subject",
  "code" : "subject",
  "base" : ["Condition"],
  "type" : "reference",
  "expression" : "Condition.subject",
  "processingMode" : "normal",
  "target" : ["Organization"],
  "modifier" : ["missing"],
  "chain" : ["name",
  "identifier"]

}