query: SELECT ?item (GROUP_CONCAT(DISTINCT(?enlabel)) as ?enlabels) WHERE 
  {  
    ?item wdt:P31 wd:Q21191270 .
    ?item wdt:P179 wd:Q23001956 .  
    OPTIONAL { ?item rdfs:label ?enlabel . FILTER(lang(?enlabel)="en")  } 
  } GROUP BY ?item ORDER BY ?item