SEWELL, R. (1988). Inprove Your Profits ...satisfying Customers Ron Sewell. W.H. Allen & Co Plc.
Chicago Style (17. basım) AtıfSEWELL, Ron. Inprove Your Profits ...satisfying Customers Ron Sewell. W.H. Allen & Co Plc, 1988.
MLA (8th ed.) AtıfSEWELL, Ron. Inprove Your Profits ...satisfying Customers Ron Sewell. W.H. Allen & Co Plc, 1988.
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