| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Zukai Yoku Wakaru Korekara No Gaichū Kanri: Naruhodo Korede Wakatta | 978-4-495-56801-6 (4-495-56801-9) | 2005 | Shin'ichi Sakata |
| Zukai yoku wakaru korekara no genka kikaku: Naruhodo korede wakatta | 978-4-495-57231-0 (4-495-57231-8) | 2006 | " |