Pour obtenir ce résultat on peut utiliser la requête suivante

PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX dbr: <http://dbpedia.org/resource/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>

SELECT distinct  ?writer ?name ?givenName ?surname  {
    { 
      ?writer a dbo:Writer.
    }
    UNION
    {
     ?writer dbo:occupation dbr:Writer.
    }
    ?writer dbo:birthPlace ?birthplace .
    ?birthplace dbo:country dbr:United_States .
    OPTIONAL { 
       ?writer foaf:surname ?surname.
    }
    OPTIONAL {
       ?writer foaf:givenName ?givenName.
    }
    OPTIONAL {
      ?writer foaf:name ?name.
    }
}