query: #title: Invalid ISSN
  # Complex constraint from [[Property talk:P236]]
  # ISSN that have wrong checksum
  SELECT ?item ?value { { ?item wdt:P236 ?value } UNION { ?statement pq:P236 ?value . ?item ?p ?statement . ?prop wikibase:claim ?p } UNION { ?ref pr:P236 ?value . ?statement prov:wasDerivedFrom ?ref . ?item ?p ?statement . ?prop wikibase:claim ?p } . BIND(REPLACE(STR(?value), "-", "") AS ?nohyphen) . FILTER(STRLEN(?nohyphen) = 8) . BIND(xsd:integer(REPLACE(SUBSTR(?nohyphen, 8, 1), "X", "10")) AS ?last) . BIND(xsd:integer(SUBSTR(?nohyphen, 1, 1)) * 8 + xsd:integer(SUBSTR(?nohyphen, 2, 1)) * 7 + xsd:integer(SUBSTR(?nohyphen, 3, 1)) * 6 + xsd:integer(SUBSTR(?nohyphen, 4, 1)) * 5 + xsd:integer(SUBSTR(?nohyphen, 5, 1)) * 4 + xsd:integer(SUBSTR(?nohyphen, 6, 1)) * 3 + xsd:integer(SUBSTR(?nohyphen, 7, 1)) * 2 AS ?checksum) . BIND(?checksum - FLOOR(?checksum / 11) * 11 AS ?remainder) . FILTER(?remainder + ?last != 11) . FILTER(?remainder + ?last != 0) }