Question: What books in the Harry Potter series were published after 2003-06-21?
Answer(s):
answer: Harry Potter and the Half-Blood Prince
answer: Harry Potter and the Deathly Hallows

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.03647x)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.03647x ns:book.book_character.appears_in_book ?x .
?x ns:book.written_work.date_of_first_publication ?num .
FILTER (?num > "2003-06-21"^^xsd:dateTime) . 
}