Barrera, R. (2005). Overpromise and overdeliver: The secrets of unshakable customer loyality. Penguin.
Čikaški stil citiranjaBarrera, Rick. Overpromise and Overdeliver: The Secrets of Unshakable Customer Loyality. New Delhi: Penguin, 2005.
MLA način citiranjaBarrera, Rick. Overpromise and Overdeliver: The Secrets of Unshakable Customer Loyality. Penguin, 2005.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.