query: # cited articles Prof. Voit
  SELECT ?pub ?pubLabel (COUNT(DISTINCT ?citedby) as ?count)
  WHERE
  { 
      ?citedby wdt:P2860 ?pub .  
      ?pub wdt:P50 wd:Q21256003 .
      SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
  }
  GROUP BY ?pub ?pubLabel
  ORDER BY DESC(?count) LIMIT 55