BMI with links to Height and Weight

{
  "resourceType": "Observation",
  "id": "bmi-using-related",
  "text": {
    "status": "generated",
    "div": "<div xmlns=\"http://www.w3.org/1999/xhtml\"><p><b>Generated Narrative with Details</b></p><p><b>id</b>: bmi-using-related</p><p><b>status</b>: final</p><p><b>category</b>: Vital Signs <span>(Details : {http://terminology.hl7.org/CodeSystem/observation-category code 'vital-signs' = 'Vital Signs', given as 'Vital Signs'})</span></p><p><b>code</b>: BMI <span>(Details : {LOINC code '39156-5' = 'Body mass index (BMI) [Ratio]', given as 'Body mass index (BMI) [Ratio]'})</span></p><p><b>subject</b>: <a>Patient/example</a></p><p><b>effective</b>: 02/07/1999</p><p><b>value</b>: 16.2 kg/m2<span> (Details: UCUM code kg/m2 = 'kg/m2')</span></p><p><b>derivedFrom</b>: </p><ul><li><a>Body Height</a></li><li><a>Body Weight</a></li></ul></div>"

  "resourceType" : "Observation",
  "id" : "bmi-using-related",
  "status" : "final",
  "category" : [{
    "coding" : [{
      "system" : "http://terminology.hl7.org/CodeSystem/observation-category",
      "code" : "vital-signs",
      "display" : "Vital Signs"
    }],
    "text" : "Vital Signs"

  },
  "status": "final",
  "category": [
    {
      "coding": [
        {
          "system": "http://terminology.hl7.org/CodeSystem/observation-category",
          "code": "vital-signs",
          "display": "Vital Signs"
        }
      ],
      "text": "Vital Signs"
    }
  ],
  "code": {
    "coding": [
      {
        "system": "http://loinc.org",
        "code": "39156-5",
        "display": "Body mass index (BMI) [Ratio]"
      }
    ],
    "text": "BMI"

  {
    "coding" : [{
      "system" : "http://loinc.org",
      "code" : "39156-5",
      "display" : "Body mass index (BMI) [Ratio]"
    }]
  }],
  "code" : {
    "coding" : [{
      "system" : "http://loinc.org",
      "code" : "39156-5",
      "display" : "Body mass index (BMI) [Ratio]"
    }],
    "text" : "BMI"

  },
  "subject": {
    "reference": "Patient/example"

  "subject" : {
    "reference" : "Patient/example"

  },
  "effectiveDateTime": "1999-07-02",
  "valueQuantity": {
    "value": 16.2,
    "unit": "kg/m2",
    "system": "http://unitsofmeasure.org",
    "code": "kg/m2"

  "effectiveDateTime" : "1999-07-02",
  "valueQuantity" : {
    "value" : 16.2,
    "unit" : "kg/m2",
    "system" : "http://unitsofmeasure.org",
    "code" : "kg/m2"

  },
  "derivedFrom": [
    {
      "reference": "Observation/bodyheight",
      "display": "Body Height"
    },
    {
      "reference": "Observation/example",
      "display": "Body Weight"
    }
  ]

  "derivedFrom" : [{
    "reference" : "Observation/bodyheight",
    "display" : "Body Height"
  },
  {
    "reference" : "Observation/example",
    "display" : "Body Weight"
  }]

}