json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "title": "Persistent identifier",
      "type": "object",
      "properties": {
          "type": {
              "title": "Type",
              "description": "Type of persistent identifier (e.g. INSPIRE_RECORD_ID)",
              "type": "string",
              "minLength": 2
          },
          "description": {
              "title": "Description",
              "description": "Short description of the identifier",
              "type": "string",
              "minLength": 1
          },
          "url": {
              "title": "URL",
              "description": "URL showing the identifier placeholder (e.g. http://inspirehep.net/record/&lt;INSPIRE_RECORD_ID&gt;)",
              "type": "string",
              "minLength": 1
          },
          "example_value": {
              "title": "Example value",
              "description": "Example value of a possible identifier (e.g. 2001192)",
              "type": "string",
              "minLength": 1
          },
          "example_url": {
              "title": "Example URL",
              "description": "Example URL with an identifier (e.g. http://inspirehep.net/record/2001192)",
              "type": "string",
              "minLength": 1
          }
      },
      "required": [
          "type",
          "description",
          "url",
          "example_value",
          "example_url"
      ],
      "additionalProperties": false
  }