query: #title: Items with P31 = [[d:Q21286738|Wikimedia permanent duplicate item <small>(Q21286738)</small>]] and P2959 should only have links to sites that the other item has as well
  # Complex constraint from [[Property talk:P2959]]
  # FIXME: Move sitelink to the other item or remove P31=Q21286738 if needed.
  SELECT DISTINCT ?item #?itemLabel ?itemDescription ?value ?valueLabel ?valueDescription ?site
  {
  	?item wdt:P31 wd:Q21286738 ; wdt:P2959 ?value;
  		^schema:about/schema:isPartOf ?site .
  	OPTIONAL {
  		?value ^schema:about/schema:isPartOf ?site1 .
  		FILTER( SAMETERM( ?site, ?site1 ) ) .
  	} .
  	FILTER( !BOUND( ?site1 ) ) .
  	#SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en" } .
  }
  ORDER BY ASC(xsd:integer(STRAFTER(str(?item), "Q")))