query: SELECT ?item ?value WHERE
  {
    ?item p:P973/ps:P973 ?value .
    
    FILTER( REGEX(REPLACE(STR(?value), "%20", " "), "^(https?://(www\\.)?nga\\.gov/content/ngaweb/Collection/artist-info\\.([1-9]\\d*)\\.html)$") )
  }