{
  "@context": {
    "dc11": "http://purl.org/dc/elements/1.1/",
    "ex": "http://example.org/vocab#",
    "ex:contains": {"@type": "@id"}
  },
  "@id": "http://example.org/test#book",
  "dc11:title": "Title",
  "ex:contains": "http://example.org/test#chapter"
}