query: SELECT ?item ?article WHERE {
    ?item wdt:P31 wd:Q7725634.
    ?item wdt:P407 wd:Q143.
      OPTIONAL {
        ?article schema:about ?item .
        ?article schema:inLanguage "eo" .
        FILTER (SUBSTR(str(?article), 1, 25) = "https://eo.wikipedia.org/")
      }
  }