What is {end time} and {start time} of {{Joseph Liouville} has {employer} as {Collège de France}}
What span of time was Joseph Liouville an employer at College de France?
When did Joseph Liouville begin and end the time as an employer at Collège de France?
SELECT ?c ?n WHERE { ?e property:start_time ?n . resource:Joseph_Liouville property:employer ?e . ?e property:end_time ?c . ?e property:employer resource:Collège_de_France }
select distinct ?value1 ?value2 where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q214549> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P108> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q202660>. ?statement <http://www.wikidata.org/entity/P580> ?value1 . ?statement <http://www.wikidata.org/entity/P2842> ?value2 } 
SELECT ?value1 ?value2 WHERE { wd:Q214549 p:P108 ?s . ?s ps:P108 wd:Q202660 . ?s pq:P582 ?value1 . ?s pq:P580 ?value2 }