query: SELECT DISTINCT ?item ?article
  WHERE
  {
    ?item wdt:P31 wd:Q5;
          wdt:P19 wd:Q8826.
    ?article a schema:Article;
               schema:about ?item;
               schema:inLanguage "ca".
    FILTER NOT EXISTS {
      ?item schema:description ?description.
      FILTER(LANG(?description) = "ca").
    }
  }