what is the {start time} for {Martha Argerich} has {spouse} as {Stephen Kovacevich} ?
Martha Argerich and Stephen Kovacevich were wed in what year?
In what year did Martha Argerich marry Stephen Kovacevich?
SELECT ?v WHERE { resource:Martha_Argerich property:spouse ?e . ?e property:spouse resource:Stephen_Kovacevich . ?e property:start_time ?v }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q156810> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P26> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q1503615> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q156810 p:P26 ?s . ?s ps:P26 wd:Q1503615 . ?s pq:P580 ?value}