| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Answering the Ultimate Question: How Net Promoter Can Transform Your Business | 978-0-470-39572-1 (0-470-39572-9) | 2008 | Richard Owen |
| Answering the Ultimate Question: How Net Promoter Can Transform Your Business | 978-0-470-39573-8 (0-470-39573-7) | 2008 | " |
| Answering the Ultimate Question: How Net Promoter Can Transform Your Business | 978-0-470-46263-8 (0-470-46263-9) | 2008 | " |