| year of publication | ISBN | author(s) | title |
|---|---|---|---|
| 2018 | 978-1-7328910-0-5 | Keenan | Gap Selling: Getting the Customer to Yes: How Problem-Centric Selling Increases Sales by Changing Everything You Know About Relationships, Overcoming Objections, Closing and Price |
| 2019 | 978-1-7328910-2-9 | Keenan | Gap Selling: Getting the Customer to Yes: How Problem-Centric Selling Increases Sales by Changing Everything You Know About Relationships, Overcoming Objections, Closing and Price |