Question: Who are the people which were the influencer of the person, who influenced Costanzo Preve ?
SPARQL:
SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Costanzo_Preve> <http://dbpedia.org/ontology/influencedBy> ?x . ?x <http://dbpedia.org/ontology/influencedBy> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Person>}