query: #title: Missing inception sourced to the catalog
  # Complex constraint from [[Property talk:P6595]]
  # Items with [[Property:P6595|Paintings by Salvador Dalí ID&#32;<small dir="ltr">(P6595)</small>]] and [[Property:P571|inception&#32;<small dir="ltr">(P571)</small>]], but it's not sourced to the catalog. Date should be checked and source should be added.
  SELECT ?item WHERE {
    ?item wdt:P6595 ?id;
      p:P571 ?inceptionstatement.
    FILTER(NOT EXISTS {
      ?inceptionstatement prov:wasDerivedFrom ?reference.
      ?reference pr:P854 ?referenceurl.
      FILTER(REGEX(STR(?referenceurl), "https://www.salvador-dali.org/en/artwork/catalogue-raisonne-paintings/obra/.*"))
    })
  }