Question: Who was in youth clubs of FC Barcelona and Newell's Old Boys?
SPARQL query:
PREFIX prop: <http://dbpedia.org/property/>
SELECT DISTINCT ?uri WHERE { ?uri prop:youthclubs <http://dbpedia.org/resource/FC_Barcelona> . ?uri prop:youthclubs <http://dbpedia.org/resource/Newell's_Old_Boys> . }