| year of publication | ISBN | author(s) | title |
|---|---|---|---|
| 1999 | 978-0-9650949-0-0 | Asking Questions Winning Sales | |
| 1997 | 978-0-9650949-1-7 | Stephan Schiffman | Asking Questions, Winning Sales: Superior Interviewing Techniques for Sales Professionals |
| 2000 | 978-0-9650949-2-4 | Stephan Schiffman | High Efficiency Selling: How Superior Salespeople Get That Way (Second Edition) |