what is the {start time} for {Juventus F.C.} has {chairperson} as {Attilio Ubertalli} ?
When was Juventus F.C. a chairman of Atillo Ubertalli?
SELECT ?value WHERE { wd:Q1422 p:P488 ?s . ?s ps:P488 wd:Q2870115 . ?s pq:P580 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q1422> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P488> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q2870115> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

Give me the year that Atillo Ubertalli's chairman was Juventus F.C.