query: #title: pattern occurring only once
  # Complex constraint from [[Property talk:P1030]]
  # may be correct, but might be malformed
  SELECT (SAMPLE(?item) as ?item) ?value (COUNT(DISTINCT ?item) as ?count) WHERE { ?item wdt:P1030 ?value } GROUP BY ?value HAVING (?count = 1) ORDER BY DESC(?value) LIMIT 1000