Question: Name the sea with Helsinki as one of the shore city and is also an outflow for Danish straits?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri WHERE {?uri prop:cities <http://dbpedia.org/resource/Helsinki> . ?uri prop:outflow <http://dbpedia.org/resource/Danish_straits>  . ?uri rdf:type onto:Sea}