Question: Who discovered Europa and Callisto?
SPARQL query:
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Europa_(moon)> prop:discoverer ?uri. <http://dbpedia.org/resource/Callisto_(moon)> onto:discoverer ?uri}