query: SELECT ?item ?viafwikidata ?ntawikidata ?person ?otheritem {
    SERVICE <http://data.bibliotheken.nl/sparql> {
    SELECT ?item ?person WHERE {
    ?person schema:mainEntityOfPage/schema:isPartOf <http://data.bibliotheken.nl/id/dataset/persons> .
    ?person schema:sameAs ?item .
    FILTER REGEX(STR(?item), "http://www.wikidata.org/entity/") .
    #FILTER(regex(?item, 'wikidata', 'i'))
    } LIMIT 15000
        }
    # The URI (wdtn) links don't seem to be fully populated
    MINUS { ?item wdtn:P1006 ?person } .
    #MINUS { ?item wdt:P1006 [] } .
    MINUS { ?item owl:sameAs ?item2 . ?item2 wdtn:P1006 ?person }
    #MINUS { ?item owl:sameAs ?item2 . ?item2 wdt:P1006 [] }
    OPTIONAL{ ?item wdtn:P214 ?viafwikidata } . 
    OPTIONAL{ ?item wdtn:P1006 ?ntawikidata } . 
    OPTIONAL { ?otheritem wdtn:P1006 ?person } .
  }
  LIMIT 15000