query: SELECT ?use ?useLabel ?p ?item ?itemLabel
  {
  	?use ?p ?item
    	VALUES ?instance { wd:Q19887878 wd:Q11266439 } 
  	?item wdt:P31 ?instance .
  	OPTIONAL { ?sitelink schema:about ?item }
    	FILTER (!BOUND(?sitelink))
  	SERVICE wikibase:label { bd:serviceParam wikibase:language "en" }
  }
  ORDER BY RAND()
  LIMIT 500