PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX yago: <http://dbpedia.org/class/yago/>
SELECT ?person
FROM <http://www.ldodds.com/ldodds-knows.rdf>
WHERE { 
	<http://www.ldodds.com#me> foaf:knows ?person . 
	?person foaf:familyName ?surname .
    	SERVICE <http://dbpedia.org/sparql> { 
		?someone rdf:type yago:ComputerPioneers ;
			    foaf:surname ?surname .
	}
}