query: SELECT ?item ?part1 ?part2 ?date
  WHERE
  {
    ?item wdt:P31 wd:Q21664088
    OPTIONAL { ?item p:P527 [ pq:P1545 "1" ; ps:P527 ?part1 ] }
    OPTIONAL { ?item p:P527 [ pq:P1545 "2" ; ps:P527 ?part2 ] }
    OPTIONAL { 
                ?item wdt:P527?/wdt:P577 ?date . 
                FILTER NOT EXISTS { ?item wdt:P527?/wdt:P577 ?date2 . FILTER( ?date2 < ?date ) }
             }
  }
  ORDER BY DESC(?date) ?item