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 .
}