Question: Give me all actors called Baldwin.
SPARQL query:
PREFIX onto:  <http://dbpedia.org/ontology/>
PREFIX res:  <http://dbpedia.org/resource/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT DISTINCT ?uri
WHERE {
        ?uri foaf:surname "Baldwin"@en . 
      { ?uri onto:occupation res:Actor . } 
      UNION 
      { ?uri rdf:type onto:Actor . }
}