PREFIX a: <http://www.w3.org/2000/10/annotation-ns#>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?given ?family
WHERE {
?annot a:annotates <http://www.w3.org/TR/rdf-sparql-query/> .
?annot dc:creator ?c .
OPTIONAL {?c foaf:given ?given ;
foaf:family ?family } .
FILTER isBlank(?c)
}