Gaya APA
Ury, W. (2008).
The power of a positive No: How to say no and still get to yes. .
London:
London Hodder Mobius.
Gaya MLA
Ury, William.
"The power of a positive No: How to say no and still get to yes. ".
London:
London Hodder Mobius,
2008.
Buku.