SCHIFFMAN STEPHAN. (2005). 25 SALES HABITS OF HIGHLY SUCCESSFUL SALESPEOPLE. ADAMS MEDIA CORPORATION.
Chicago-viite (17. p.)SCHIFFMAN STEPHAN. 25 SALES HABITS OF HIGHLY SUCCESSFUL SALESPEOPLE. MASSACHUETTS: ADAMS MEDIA CORPORATION, 2005.
MLA-viite (9. p.)SCHIFFMAN STEPHAN. 25 SALES HABITS OF HIGHLY SUCCESSFUL SALESPEOPLE. ADAMS MEDIA CORPORATION, 2005.
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