{
  "$id": "https://schemas.opendd.eu/xtdexternaldocument.1.schema.json",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "xtd External document Schema",
  "description": "According to SS-EN ISO 12006-3:2022",
  "allOf": [
    {
      "$ref": "/xtdroot.1.schema.json"
    },
    {
      "$ref": "/xtdobject.1.schema.json"
    },
    {
      "$ref": "/xtdconcept.1.schema.json"
    },
    {
      "$ref": "#/$defs/xtdExternalDocument"
    }
  ],
  "$defs": {
    "xtdExternalDocument": {
      "type": "object",
      "properties": {
        "DateOfPublication": {
          "description": "The publication date of the external document.",
          "$ref": "/xtddatetime.1.schema.json"
        },
        "Author": {
          "description": "Information about the author of the document.",
          "type": "string"
        },
        "ISBN": {
          "description": "The International Standard Book Number is a numeric commercial book identifier which is intended to be unique",
          "type": "string"
        },
        "Languages": {
          "description": "Set of languages of the external document.",
          "type": "array",
          "minItems": 1,
          "items": {
            "$ref": "/opendd-entityref.1.schema.json"
          }
        },
        "Publisher": {
          "description": "Information about who published the external document.",
          "type": "string"
        },
        "URI": {
          "description": "Link to the external document.",
          "type": "string"
        }
      },
      "required": [
        "Languages"
      ]
    }
  }
}