What is {discovered} of {generation unit} of {steam locomotive} ?
Give me the name of the discoverer of the generation unit for the steam locomotive.
Who discovered the generation unit of the steam locomotive?
SELECT ?h WHERE { ?m property:time_of_discovery_or_invention ?h . resource:steam_locomotive property:powered_by ?m }
SELECT ?answer WHERE { ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q171043> . ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P516>. ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?X . ?statement2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?X. ?statement2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P575> . ?statement2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?answer . }
SELECT ?answer WHERE { wd:Q171043 wdt:P516 ?X . ?X wdt:P575 ?answer}
1884-01-01T00:00:00Z