query: select ?item ?itemLabel ?article_WPNL ?article_WPEN
  where {
    ?item p:P195 ?st .
    ?st ps:P195 wd:Q1526131 .
    ?st pq:P2868 wd:Q29188408
  
  OPTIONAL {
      ?article_WPNL schema:about ?item.
      ?article_WPNL schema:isPartOf <https://nl.wikipedia.org/>.
    }
  OPTIONAL {
      ?article_WPEN schema:about ?item.
      ?article_WPEN schema:isPartOf <https://en.wikipedia.org/>.
    }
  
          SERVICE wikibase:label { bd:serviceParam wikibase:language "nl". }
  }