PREFIX dc:  <http://purl.org/dc/elements/1.1/>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

DELETE
 { ?book ?p ?v }
WHERE
 { ?book dc:date ?date .
   FILTER ( ?date > "1970-01-01T00:00:00-02:00"^^xsd:dateTime )
   ?book ?p ?v
 }
