What is the {bus station} for {place served by transport hub} of {Belgrade}
Which is the bus station for the place served by transport hub of Belgrade?
 select distinct ?sbj where { ?sbj wdt:P931 wd:Q3711 . ?sbj wdt:P31 wd:Q494829 } 
select distinct ?subj where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?subj . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P931> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q3711> . ?subj <http://www.wikidata.org/entity/P31> <http://wikidata.dbpedia.org/resource/Q494829> } 
Which is the transport station for the put served by transport center of Belgrade?