使用SPARQL,如何通过identifer选择节点,特别是在wikidata中？

使用维基数据SPARQL服务,我想获得50个州的列表,并包括维基数据区的哥伦比亚特区.我想出了一个kludgy查询来做到这一点:

#-- wdt:P31 = instance of;  wd:Q35657 = list of states

SELECT ?state ?stateLabel
   WHERE {
     {?state wdt:P31 wd:Q35657} UNION 
     {?state wdt:P3403 wd:Q3551781} . #-- coextensive with District of Columbia
   SERVICE wikibase:label { bd:serviceParam wikibase:language "en" }
}

UNION {?state == wd:Q61}

SELECT ?state ?stateLabel WHERE {
     {?state wdt:P31 wd:Q35657} 
       UNION 
     {BIND(wd:Q61 as ?state)}
     SERVICE wikibase:label { bd:serviceParam wikibase:language "en" }
}