# Free piston engines

{
  "id": "S85051667",
  "title": "Free piston engines",
  "url": "/topics/S85051667",
  "kind": "topic-directory",
  "aeo_cohort": "topic-directory",
  "provider": "lcsh",
  "revision": "c3a6b31718757649",
  "catalogue_revision": "f050b5d4780b1289",
  "numeric_address": "864845352145126912",
  "address_version": "morton4x16-v1",
  "coordinates": [
    0,
    20,
    18212,
    19456
  ],
  "answer_status": "Directory metadata; local answer requires separate source review",
  "truth_status": "Subject descriptor, not a factual answer or a demonstrated knowledge gap"
}



Directory metadata is not a factual answer or evidence of a global knowledge gap.

Source: https://id.loc.gov/authorities/subjects/sh85051667

No owner-reviewed local answer yet.