Metamorphous Press · Ninestar Publishing
| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Enneagram Applications | 978-1-55552-103-5 (1-55552-103-7) | 2001 | Thomas Condon |
| Out of the Box: Coaching with the Enneagram | 978-0-9763159-0-2 (0-9763159-0-4) | 2005 | Mary Bast |
| Parables and the Enneagram | 978-1-55552-106-6 (1-55552-106-1) | 2002 | |