Question: Who was the wife of President Lincoln?
SPARQL:
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX foaf: <http://xmlns.com/foaf/0.1/> PREFIX onto: <http://dbpedia.org/ontology/> SELECT ?uri ?string WHERE { ?person rdf:type onto:President . ?person foaf:surname 'Lincoln'@en . ?person onto:spouse ?uri. OPTIONAL {?uri rdfs:label ?string . FILTER (lang(?string) = 'en') } }