query: SELECT DISTINCT ?item ?itemLabel ?andereCollecties ?RKD_url WHERE {
    ?item wdt:P6379 wd:Q2191118.
    OPTIONAL { ?item wdt:P650 ?RKDid. }
     BIND(IRI(CONCAT('https://rkd.nl/nl/explore/artists/',?RKDid)) AS ?RKD_url)
    ?item wdt:P6379 ?collecties
    BIND(?collecties =  wd:Q2191118 AS ?eigencollectie).
    BIND(IF(?eigencollectie,"", ?collecties) AS ?andereCollecties).
   MINUS {  ?item wdt:P31 wd:Q5.}
   MINUS {  ?item wdt:P6379 wd:Q2042754.}
  }