Barrera, R. (2005). Overpromise and overdeliver: The secrets of unshakable customer loyality. Penguin.
Παραπομπή Chicago StyleBarrera, Rick. Overpromise and Overdeliver: The Secrets of Unshakable Customer Loyality. New Delhi: Penguin, 2005.
Παραπομπή MLABarrera, Rick. Overpromise and Overdeliver: The Secrets of Unshakable Customer Loyality. Penguin, 2005.
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