query: #title: Check prefixes
  # Complex constraint from [[Property talk:P4801]]
  #
  SELECT ?item ?marc ?prefix {
    ?item wdt:P4801 ?marc.
    BIND (STRBEFORE(?marc, "/") AS ?prefix).
    FILTER (?prefix NOT IN ("countries", "languages", "relators", "geographicAreas", 
                            "subjectSchemes", "marcgt", "ethnographicTerms", "resourceTypes", "identifiers", "organizations"))
  }