What is {end time} and {start time} of {{Belgrade} has {country} as {Principality of Serbia}}
What date did Belgrade begin and cease being a country as a Principality of Serbia?
When did Belgrade start and end being a country as a Principality of Serbia?
SELECT ?t ?q WHERE { ?f property:country resource:Principality_of_Serbia . resource:Belgrade property:country ?f . ?f property:start_time ?q . ?f property:end_time ?t }
select distinct ?value1 ?value2 where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q3711> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P17> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q684030>. ?statement <http://www.wikidata.org/entity/P580> ?value1 . ?statement <http://www.wikidata.org/entity/P2842> ?value2 } 
SELECT ?value1 ?value2 WHERE { wd:Q3711 p:P17 ?s . ?s ps:P17 wd:Q684030 . ?s pq:P582 ?value1 . ?s pq:P580 ?value2 }