Question: Name the scientist whose supervisor also supervised Mary Ainsworth?
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:doctoralStudents <http://dbpedia.org/resource/Mary_Ainsworth> . ?uri prop:doctoralAdvisor ?x . ?uri rdf:type onto:Scientist}