What is {date of death} of {John X} that is {sourcing circumstances} is {presumably} ?
When is John X believed to have died?
What is John X's persumed date of date according to sourcing circumstances?
SELECT ?r WHERE { ?a property:sourcing_circumstances resource:presumably . ?a property:date_of_death ?r . resource:John_X property:date_of_death ?a }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q227976> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P570> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P1480> <http://wikidata.dbpedia.org/resource/Q18122778>
} 

SELECT ?obj WHERE { wd:Q227976 p:P570 ?s . ?s ps:P570 ?obj . ?s pq:P1480 wd:Q18122778 }