query: SELECT ?item ?itemLabel ?p21 ?p21Label WHERE {
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
    ?item (wdt:P21/wdt:P279*) wd:Q189125.
    ?item wdt:P106 wd:Q82955.
    OPTIONAL { ?item wdt:P21 ?p21. }
  }