period duration

{
  "id": "NISTq109",
  "unitsml_id": "q:period_duration",
  "name": "period duration",
  "names": [
    {
      "value": "period duration",
      "lang": "en"
    },
    {
      "value": "period",
      "lang": "en"
    }
  ],
  "short": "period_duration",
  "type": "derived",
  "dimension": {
    "id": "NISTd3",
    "name": "time",
    "expression": "T",
    "components": [
      {
        "key": "time",
        "symbol": "T",
        "power": 1
      }
    ],
    "dimensionless": false
  },
  "units": [
    {
      "id": "NISTu3",
      "name": "second",
      "symbol": "″"
    }
  ],
  "unit_count": 1,
  "identifiers": [
    {
      "type": "nist",
      "id": "NISTq109"
    },
    {
      "type": "unitsml",
      "id": "q:period_duration"
    }
  ],
  "references": [
    {
      "type": "informative",
      "authority": "qudt",
      "uri": "http://qudt.org/vocab/quantitykind/Period"
    }
  ]
}