query: SELECT ?item ?nr_all (GROUP_CONCAT(DISTINCT ?delabel) AS ?delabels) WHERE {
    ?item wdt:P31/wdt:P279* wd:Q21191270.
    
  
     ?item p:P179 ?series_statement .
     ?series_statement ps:P179 wd:Q1306748 .
      ?series_statement pq:P1545 ?nr_all.
    
    OPTIONAL {
      ?item rdfs:label ?delabel.
      FILTER((LANG(?delabel)) = "de")
    }
  }
  GROUP BY ?item ?nr_all
  ORDER BY xsd:integer(?nr_all)