query: SELECT ?itemLabel (COUNT(?date) as ?count) 
  WHERE
  {
     { ?item wdt:P31/wdt:P279* wd:Q23019040 }  
     ?item wdt:P571 ?date
     SERVICE wikibase:label { bd:serviceParam wikibase:language "fr". }
  }
  GROUP BY ?itemLabel
  HAVING (?count > 1)
  
  