query: SELECT DISTINCT ?item ?itemLabel ?instc
  WHERE 
  {
    ?item wdt:P31 wd:Q15911738.      
    ?item wdt:P2109 ?instc. 
    OPTIONAL { ?item wdt:P625 ?coor } . 
    MINUS { ?item wdt:P31 wd:Q811683 } .
    MINUS { ?item wdt:P31 wd:Q12377751 } .
  }
  ORDER BY DESC(?instc)
  LIMIT 20