Question: Which key perosn of the Elders is also the president of united World College?
SPARQL query: SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/The_Elders_(organization)> <http://dbpedia.org/property/keyPeople> ?uri. <http://dbpedia.org/resource/United_World_Colleges> <http://dbpedia.org/ontology/president> ?uri}
Answer: [Nelson Mandela] is a key person of The Elders and president of United World Colleges.