Godin, S. (1999). Permission marketing: Strangers into friends into customers. Simon & Schuster.
Dyfyniad Arddull ChicagoGodin, Seth. Permission Marketing: Strangers into Friends into Customers. London: Simon & Schuster, 1999.
Dyfyniad MLAGodin, Seth. Permission Marketing: Strangers into Friends into Customers. Simon & Schuster, 1999.
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