Ries, A. (1993). The 22 immutable laws of marketing. New York: Harper Business.
Trích dẫn kiểu ChicagoRies, Al. The 22 Immutable Laws of Marketing. New York: Harper Business, 1993.
Deismireacht MLARies, Al. The 22 Immutable Laws of Marketing. New York: Harper Business, 1993.
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