What is the {human} for {student of} of {Warren Buffett}
Who was a understudy of Warren Buffett?
Who was a student of Warren Buffett?
SELECT DISTINCT ?d WHERE { ?d rdf:type ontology:human . resource:Warren_Buffett property:student_of ?d }
select distinct ?obj where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q47213> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1066> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj . ?obj <http://www.wikidata.org/entity/P31> <http://wikidata.dbpedia.org/resource/Q5> } 
 select distinct ?obj where { wd:Q47213 wdt:P1066 ?obj . ?obj wdt:P31 wd:Q5 } 
Benjamin Graham