| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Eleuthera | 978-0-9832821-0-5 (0-9832821-0-2) | 2011 |
| Empowering Excellence - An Executive Guide to Continuous Improvement | 978-0-9832821-9-8 (0-9832821-9-6) | 2014 |
R. E. · Ralf Ek · Ralph Eck · Ralph Eis · Rolf Eicke