query: #defaultView:BubbleChart
  #Institutions of the most cited authors who have published papers on Zika virus or Zika fever, on Ebola virus or Ebola fever
  SELECT ?employer ?employerLabel (COUNT(?paper) AS ?count)
  WHERE
  {
      ?item wdt:P2860 ?paper .
      VALUES ?topics { wd:Q10538943 wd:Q51993 wd:Q202864 wd:Q8071861 }
      { ?paper wdt:P921 ?topics . } 
      ?paper wdt:P50 ?author .
      ?author wdt:P108 ?employer .
      SERVICE wikibase:label {
          bd:serviceParam wikibase:language "en" .
      }
  }
  GROUP BY ?employer ?employerLabel
  ORDER BY DESC(?count)