what is the {start time} for {Raymond Aron} has {employer} as {Collège de France} ?
What year did Raymond Aron begin work at the Collège de France?
When did Raymond Aron start working at Collège de France?
SELECT ?d WHERE { ?c property:employer resource:Collège_de_France . ?c property:start_time ?d . resource:Raymond_Aron property:employer ?c }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q160640> .
?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> ?value. 
} 

SELECT ?value WHERE { wd:Q160640 p:P108 ?s . ?s ps:P108 wd:Q202660 . ?s pq:P580 ?value}