{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://readium.org/guided-navigation/schema/description.schema.json",
  "title": "Readium Guided Navigation Description Object",
  "type": "object",
  "properties": {
    "audioref": {
      "type": "string",
      "format": "uri-reference"
    },
    "imgref": {
      "type": "string",
      "format": "uri-reference"
    },
    "textref": {
      "type": "string",
      "format": "uri-reference"
    },
    "videoref": {
      "type": "string",
      "format": "uri-reference"
    },
    "text": {
      "$ref": "text.schema.json"
    }
  },
  "anyOf": [
    {
      "required": ["audioref"]
    },
    {
      "required": ["imgref"]
    },
    {
      "required": ["textref"]
    },
    {
      "required": ["videoref"]
    },
    {
      "required": ["text"]
    }
  ]
}