query: #title: Check prefix 'languages'
  # Complex constraint from [[Property talk:P4801]]
  #
  SELECT ?item ?value ?marc {
  	?item wdt:P220 ?value.
    ?item wdt:P4801 ?marc.
    BIND (SUBSTR(?marc, 1, 9) AS ?prefix).
    FILTER (?prefix NOT IN ("languages"))
  }