Dyfyniad APA

Barrera, R. (2005). Overpromise and overdeliver: The secrets of unshakable customer loyality. Penguin.

Dyfyniad Arddull Chicago

Barrera, Rick. Overpromise and Overdeliver: The Secrets of Unshakable Customer Loyality. New Delhi: Penguin, 2005.

Dyfyniad MLA

Barrera, Rick. Overpromise and Overdeliver: The Secrets of Unshakable Customer Loyality. Penguin, 2005.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.