query: #Find common strings for authors of scientific articles on the Zika virus
  SELECT * WHERE {
    {
      SELECT ?authorstring (COUNT(DISTINCT ?paper) AS ?count) (GROUP_CONCAT(DISTINCT ?paper; SEPARATOR = " , ") AS ?items) WHERE {
        ?paper wdt:P2093 ?authorstring;
  #             wdt:P50 ?author;
               wdt:P921 wd:Q202864 .
      }
      GROUP BY ?authorstring
    }
    FILTER(?count > 4)
  }
  ORDER BY DESC(?count)