Question: Whose leaders are Willem-Alexander and Fredis Refunjol?
SPARQL:
SELECT DISTINCT ?uri WHERE { ?uri <http://dbpedia.org/ontology/leader> <http://dbpedia.org/resource/Willem-Alexander_of_the_Netherlands> . ?uri <http://dbpedia.org/ontology/leader> <http://dbpedia.org/resource/Fredis_Refunjol> . }