Question: Who was the parent of person whose child is William C P breckinridge?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri WHERE { ?x prop:children <http://dbpedia.org/resource/William_Campbell_Preston_Breckinridge> . ?x onto:parent ?uri  . ?x rdf:type onto:Person}