Question: Who wrote the book The pillars of the Earth?
SPARQL query:
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT ?uri ?string
WHERE 
{
	?books rdf:type onto:Book .
        ?books onto:author ?uri .
        ?books rdfs:label 'The Pillars of the Earth'@en .
	OPTIONAL {?uri rdfs:label ?string . FILTER (lang(?string) = 'en') }
}