query: PREFIX wikibase: <http://wikiba.se/ontology#>
  PREFIX wd: <http://www.wikidata.org/entity/> 
  PREFIX wdt: <http://www.wikidata.org/prop/direct/>
  PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
  PREFIX p: <http://www.wikidata.org/prop/>
  PREFIX v: <http://www.wikidata.org/prop/statement/>
  
  SELECT ?publisher ?publisherLabel (COUNT(?p) AS ?count) WHERE {
  #SELECT ?p ?pLabel ?author ?authorLabel ?publisher ?publisherLabel ?date WHERE {
     ?c wdt:P279* wd:Q571 .
     ?p wdt:P31 ?c .
     #OPTIONAL {?p wdt:P50 ?author .} 						#author
     #OPTIONAL {?p wdt:P123 ?publisher .}                      # publisher
     ?p wdt:P123 ?publisher .                      # publisher
     #?p wdt:P577 ?date .
    
     SERVICE wikibase:label {
      bd:serviceParam wikibase:language "en" .
     }
   }
  GROUP BY ?publisher ?publisherLabel
  ORDER BY DESC(?count)
  LIMIT 100