query: SELECT ?item ?itemLabel ?startTime ?endTime WHERE {
    ?item p:P39 ?statementNode .
    ?statementNode ps:P39 wd:Q17481175 .
    OPTIONAL {
      ?statementNode pq:P580 ?startTime .
    }
    OPTIONAL {
      ?statementNode pq:P582 ?endTime .
    }
    SERVICE wikibase:label { bd:serviceParam wikibase:language 'de,en' }
  }   