json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "description": "This schema represents a numerical value with a unit of measure.",
      "type": "object",
      "properties": {
          "value": {
              "description": "The numeric value of the element.",
              "type": "number"
          },
          "unit": {
              "references": [
                  {
                      "description": "The unit of measure of the element. Allowed values are drawn from the Common synonyms (non-UCUM) column of [subset of] UCUM, SI and English units. ",
                      "url": "http://www.hl7.de/download/documents/ucum/ucumdata.html"
                  }
              ],
              "type": "string"
          }
      },
      "required": [
          "value",
          "unit"
      ]
  }