query: #title: Property should be used on items with a sitelink to Wikisource
  # Complex constraint from [[Property talk:P6695]]
  #
  SELECT ?item 
  WHERE
  {
  	?item wdt:P6695 [] .
      FILTER NOT EXISTS { ?item ^ schema:about / schema:isPartOf / wikibase:wikiGroup "wikisource" } 
  }
  LIMIT 100