Question: Who has authored books published by the Perkins school for the Blind?
SPARQL query: SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/publisher> <http://dbpedia.org/resource/Perkins_School_for_the_Blind> . ?x <http://dbpedia.org/ontology/author> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/WrittenWork>}
Answer: The author of the work published by Perkins School for the Blind is [Helen Keller].