Get a book by external id

{
  "data": {
    "id": "e9e0d212-52cb-11f1-8d0d-aedf0546306a",
    "type": "book",
    "attributes": {
      "format": "ebook",
      "status": "draft",
      "title": "Sample Ebook",
      "externalId": "ext-001",
      "subtitle": null,
      "series": null,
      "language": [
        "EN"
      ],
      "isbn": null,
      "imprint": {
        "id": "e9e8d15e-52cb-11f1-8d0d-aedf0546306a",
        "name": "Demo Imprint"
      },
      "description": "A sample ebook.",
      "category": [
        "FIC002000"
      ],
      "keyword": [
        "sample"
      ],
      "copyright": "SELF",
      "saleTerritory": [
        "ALL"
      ],
      "publicationDate": "2027-06-15",
      "isFinalVersion": false,
      "contributor": [
        {
          "firstName": "Jane",
          "lastName": "Doe",
          "role": "Author"
        }
      ],
      "price": [
        {
          "currency": "USD",
          "price": 9.99
        }
      ],
      "audience": null,
      "ebookDetails": {
        "pageCount": 200,
        "kdpEnrolled": false,
        "publishedOnAmazon": false
      },
      "podDetails": null,
      "audioDetails": null,
      "files": [],
      "chapters": null
    }
  }
}

{
  "title": "Response message failed validation",
  "status": 400,
  "detail": "Response message failed validation; Missing required header \"Content-Type\" for Response [get /api/books/external-id/{bookExternalId} 403]",
  "instance": "/v2/distribution/books/external-id/ext-001",
  "invalidParams": []
}