| title | ISBN-13 | year of publica- tion | |
|---|---|---|---|
| Crowning the Customer: How to Become Customer-driven | 978-0-86278-952-7 | 2005 | |
| Crowning the Customer: How to Become Customer-Driven | 978-0-86278-763-9 | 2002 | |
| Crowning the Customer: How to Become Customer-Driven | 978-0-86278-242-9 | 1990 | |
| Wie König Kunde die Warteschlange fraß | 978-3-933974-39-6 | 2004 |