what is the {start time} for {Doris Lessing} has {spouse} as {Gottfried Lessing} ?
When were Gottfried Lessing and Doris Lessing married?
When was Doris Lessing the spouse of Gottfried Lessing?
SELECT ?v WHERE { ?v property:start_time ?v . ?v property:spouse resource:Gottfried_Lessing . resource:Doris_Lessing property:spouse ?v }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q40874> .
?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/Q215347> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q40874 p:P26 ?s . ?s ps:P26 wd:Q215347 . ?s pq:P580 ?value}